Bryant 541A Users Manual

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2015-02-02

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installation, start-up and
service instructions

575B/575C/541A
Sizes 072-180
6 to 15 Tons

AIR-COOLED SPLIT SYSTEM
HEAT PUMP
Cancels:

II 575B-72-3

II 575B-72-4
9/15/04

INSTALLATION

CONTENTS
Page
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . 1

I. COMPLETE PRE-INSTALLATION CHECKS

GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-14
I. Complete Pre-Installation Checks . . . . . . . . . . . . . . 1
II. Rig and Mount Unit . . . . . . . . . . . . . . . . . . . . . . . . . . 1
III. Complete Refrigerant Piping
Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
IV. Complete Electrical Connections. . . . . . . . . . . . . . . 9
PRE-START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15,16

Remove unit packaging except for the top skid assembly,
which should be left in place until after the unit is rigged
into its final location.

START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16-18
SEQUENCE OF OPERATION. . . . . . . . . . . . . . . . . . . . . .18-20
SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20-24
TROUBLESHOOTING. . . . . . . . . . . . . . . . . . . . . . . . . . . . 25,26
START-UP CHECKLIST . . . . . . . . . . . . . . . . . . . . . CL-1, CL-2
SAFETY CONSIDERATIONS
Installing, starting up, and servicing air-conditioning equipment can be hazardous due to system pressures, electrical
components, and equipment location (roofs, elevated structures, etc.).
Only trained, qualified installers and service mechanics
should install, start-up, and service this equipment.
Untrained personnel can perform basic maintenance functions such as cleaning coils. All other operations should be
performed by trained service personnel.
When working on the equipment, observe precautions in
the literature and on tags, stickers, and labels attached to
the equipment.
Follow all safety codes. Wear safety glasses and work gloves.
Keep quenching cloth and fire extinguisher nearby when
brazing. Use care in handling, rigging, and setting bulky
equipment.
WARNING: Before installing or servicing system,
always turn off main power to system and install lockout tag on disconnect. There may be more than one disconnect switch. Electrical shock can cause personal
injury.
GENERAL
The split system heat pump units described in this book are
designed for use with the 524A-H indoor packaged air
handler sections only.

A. Uncrate Unit

B. Inspect Shipment
File claim with shipping company if shipment is damaged or
incomplete.
C. Consider System Requirements
• Consult local building codes and National Electrical Code
(NEC) for special installation requirements.
• Allow sufficient space for airflow clearance, wiring, refrigerant piping, and servicing unit. See Fig. 1-3 for unit
dimensions. Figure 4 shows typical component locations
for 541A180 units.
• Locate unit so that outdoor coil airflow is unrestricted on
all sides and above.
• Unit may be mounted on a level pad directly on the base
channels or mounted on raised pads at support points.
See Table 1 for unit operating weights.
II. RIG AND MOUNT UNIT
CAUTION: Be sure unit panels are securely in
place prior to rigging. Be careful rigging, handling, and
installing unit. Improper unit location can cause system malfunction and material damage. Inspect base
rails for any shipping damage and make sure they are
fastened securely to unit before rigging.
A. Rigging
These units are designed for overhead rigging. Refer to rigging label for preferred rigging method. Spreader bars are
not required if top crating is left on unit. All panels must be
in place when rigging. As further protection for coil faces,
plywood sheets may be placed against sides of unit, behind
cables. Run cables to a central suspension point so that angle
from the horizontal is not less than 45 degrees. Raise and set
unit down carefully.
If it is necessary to roll the unit into position, mount the unit
on field-supplied rails placed lengthwise under the unit,
using a minimum of 3 rollers. Apply force to the rails, not the
unit. If the unit is to be skidded into position, place it on a
large pad and drag it by the pad. Do not apply any force to
the unit.
Raise from above to lift unit from the rails or pad when unit
is in final position.
After unit in position, remove all shipping materials and top
crating.

B. Locate Unit
For service access and unrestricted airflow, provide clearance
on each end and side of unit. Position unit so that there is
unrestricted airflow above unit.

C. Mount Unit
The unit may be mounted on a solid, level concrete pad, on
accessory mounting legs, or on field-supplied raised supports
at each mounting position. (Note that mounting hardware is
field supplied.)
Bolt unit securely to pad or supports after unit is in position
and is level. Be sure to mount unit level to ensure proper oil
return to compressors. Mounting holes on unit can be used to
secure unit to vibration isolators, if required.

NOTE: Before mounting unit, remove holddown brackets and
release skid.
If conditions or local codes require unit to be fastened to pad,
use the mounting holes in the base rails.

CONTROL BOX

B
FRONT
7/8
4 PLACES

19 3/8
27

Line & Low
Voltage Wiring
Entrances

5-3/4

38-1/2

1-1/2
24 1/2
24

9-3/4

10 C

2-1/8
1-1/8

4 7/8
33

2-1/2
4-1/4

1-1/2

REAR

BOTTOM

38-1/2

1-1/2

TOP

1-1/2

FRONT

NOTES:
1. All dimensions are in inches.
2. Recommended clearance for proper airflow (local codes or jurisdictions may prevail):
Top — 60 in.
Sides — 24 in. on 3 sides, one side may be 6 in. (Control box side should have 24-in. clearance for service
access.)
3. Corner Weights (lb): A = 86
B = 84
C = 92
D = 90

Fig. 1 — 575B072 Unit Dimensions

—2 —

—3—
Fig. 2 — 575C090,120 Unit Dimensions

WEIGHT DISTRIBUTION
UNIT
541A
180

WEIGHT — lb (kg)
Total
Support Point
Operating
1
2
3
4
Weight
803
(364)

158 243 244 158
(72) (110) (111) (72)

NOTE: Recommended service clearances are as
follows (local codes or jurisdictions may prevail):
Side (compressor) — 31/2 ft (1067 mm)
Side (opposite compressor) — 3 ft (914 mm)
Ends — 2 ft (616 mm)
Top — 5 ft (1524 mm)

Fig. 3 — 541A180 Unit Dimensions

—4 —

14
15

1
2
3
4
5
6
7
8
9
10

—
—
—
—
—
—
—
—
—
—

Defrost Board/Time Guard II Control
Fuse
Fan No. 1
Compressor Lockout (CLO) Device
Outdoor-Fan Relay
Outdoor-Fan Contactor
Compressor Contactor
Fan Motor Capacitors
Circuit Breaker
Fan No. 2

LEGEND
11 — Power Terminal Block
12 — Control Terminal Block
13 — Compressor Lockout (CLO2 for
Crankcase Heater)
14 — Control Relay (CR3)
15 — Liquid Line Solenoid
16 — Control Relay (CR2)
17 — No Dump Relay (NDR)
18 — Oil Pressure Switch
19 — Fusible Plug (hidden)

20
21
22
23
24
25
26
27
28

Fig. 4 — Component Locations — 541A180 Shown

—5—

—
—
—
—
—
—
—
—
—

High-Pressure Switch
Compressor
Capacity Control Solenoid
Filter Drier
Muffler
Oil Solenoid
Reversing Valve
Accumulator
Coil

Table 1 — Physical Data — 575B072, 575C090,120 and 541A180 Units
UNIT
NOMINAL CAPACITY (tons)
OPERATING WEIGHTS (lb)
Aluminum-Fin Coils (standard)
Copper-Fin Coils (optional)
REFRIGERANT*
Operating Charge, Typical (lb)†
Shipping Charge (lb)
COMPRESSOR
Qty...Model
Oil Charge (oz)
No. Cylinders
Speed (rpm)
OUTDOOR FANS
Qty...Rpm
Diameter (in.)
Nominal Hp
Nominal Airflow (cfm total)
Watts (total)
OUTDOOR COILS (Qty)
Face Area (sq ft total)
Rows...Fins/in.
Storage Capacity (lb)**
CONTROLS
Pressurestat Settings (psig)
High Pressure
Open
Close
Low Pressure
Open
Close
PIPING CONNECTIONS (in. ODM)
Vapor
Liquid

575B072
6

575C090
7.5

345
N/A

464
565

20
1

20
9
Scroll
1...ZR_94
90
N/A
3500

1...SR_75
88

575C120
10
506
607
R-22
22
9
1...ZR125
110

541A180
15
803
945
37
3
Semi-hermetic reciprocating
1...06DF537††
128
6
1750

1…1100
26
3/
4
6300
750
1
24
2…18
17.3

2…1100
22
1/
4
6500
570
2
29.2
2…17
34.2

2…1075
26
1/
2
11,000
1460
1
29.2
3…15
40.1

420
300

428 ± 10
320 ± 20

395 ± 20
295 ± 20

5
20

7±3
22 ± 5

11 / 8
5/
8

11/8
1/ 2

*Unit is factory supplied with holding charge only.
†Typical operating charge with 25 ft of interconnecting pipe.
**Storage capacity of condenser coil with 80% full of liquid at 95 F.
††Equipped with an electric solenoid unloader, capacity steps are 100% and 67%.

—6 —

13 / 8
1/2

15 / 8
5/8

unit to outdoor unit before opening the liquid and vapor lines at
the outdoor unit. For specific filter driers see Table 4.

III. COMPLETE REFRIGERANT PIPING CONNECTIONS
Refrigerant lines must be carefully designed and constructed
to ensure equipment reliability and efficiency. Line length,
pressure drop, compressor oil return, and vertical separation
are several of the design criteria that must be evaluated. See
Table 2.

D. Liquid Line Piping Procedure
Pipe the system liquid line as follows:
WARNING: Unit is pressurized with a holding
charge of refrigerant. Recover R-22 holding charge
before removing runaround liquid piping loop. Failure
to recover holding charge before removing piping loop
could result in equipment damage and personal injury.

IMPORTANT: Do not bury refrigerant piping underground.
IMPORTANT: Piping must be properly sized and installed for
the system to operate efficiently.
A. Check Vertical Separation

1. Open service valves in sequence:
a. Discharge service valve on compressor.
b. Suction service valve on compressor.
c. Liquid line valve.

If there is any vertical separation between the indoor and outdoor units, check to ensure that the separation is within
allowable limits. Relocate equipment if necessary. See Table 3.
B. Refrigerant Line Sizing
Consider the length of the piping required between the outdoor and indoor units. The maximum allowable line length is
100 ft. See Table 3. Refrigerant suction piping should be
insulated.
IMPORTANT: A refrigerant receiver is not provided with the
unit. Do not install a receiver.
IMPORTANT: For 575C090,120 applications with liquid lift
greater than 20 ft, use 5/8-in. liquid line. Maximum lift is
60 ft.

2. Remove 1/4-in. flare cap from liquid valve Schrader
port.
3. Attach refrigerant recovery device and recover holding charge.
4. Remove runaround loop (581A180 only).
5. Connect system liquid line from liquid connection of
outdoor unit (575B,C, 541A) to indoor unit (524A-H)
liquid line connections. Select proper field-supplied
bi-flow filter driers and install in the liquid line. See
Fig. 5. Install a field-supplied liquid moisture indicator between the filter drier(s) and the liquid connections on the indoor unit. Braze or silver alloy solder
all connections. Pass nitrogen or other inert gas
through piping while making connections to prevent
formation of copper oxide. (Copper oxides are
extremely active under high temperature and pressure. Failure to prevent collection of copper oxides
may result in system component failures.)

Table 2 — Refrigerant Piping Sizes

575B072

1/ 2

LENGTH OF PIPING ft
26-60
61-100
Line Size (in. OD)
V
L
V
L
V
5/ 8
5/ 8
11/8
11/8
11/8

575C090

11/8

575C120

13/8

541A180

15/8

0-25

OUTDOOR
UNIT
L

11/8

13/8

15/8

MAXIMUM
LIQUID
LINE
(in. OD)*
5/ 8

11/8

13/8

15/8

*If there is a vertical separation between indoor and outdoor units, see
Table 3 — Maximum Vertical Separation.
LEGEND
L — Liquid Line
V — Vapor Line
NOTES:
1. Pipe sizes are based on a 2 F loss for liquid and vapor lines.
2. Pipe sizes are based on the maximum linear length, shown for each
column, plus a 50% allowance for fittings.
3. Charge units with R-22 refrigerant in accordance with unit installation
instructions.
4. Maximum line length must not exceed 100 ft.
5. Do not bury refrigerant piping.

E. Liquid Line Solenoid Valve
Addition of a liquid solenoid valve (LLSV) is required (except
for 541A180 units that already have LLSV factory-installed).
The LLSV must be a bi-flow type suited for use in heat pump
systems. Refer to Table 4. Wire the solenoid valve in parallel
with the compressor contactor coil.
The LLSV must be installed at the outdoor unit with the
flow arrow pointed toward the outdoor unit (in-flow direction
for the Heating mode).

Table 3 — Maximum Vertical Separation*
OUTDOOR
UNIT
575B
575C
541A

072
090
120
180

INDOOR UNIT
524A-H
090
090
120
180

DISTANCE FT
Outdoor Unit
Above 524A-H
50
60
60
80

*Vertical distance between indoor and outdoor units.

C. Install Filter Drier(s) and Moisture Indicator(s)
Every unit should have a filter drier and liquid-moisture
indicator (sight glass). In some applications, depending on
space and convenience requirements, it may be desirable to
install 2 filter driers and sight glasses. One filter drier and
sight glass may be installed at A locations in Fig. 5. If
desired, 2 filter driers and sight glasses may be installed at
B locations in Fig. 5.
Select the filter drier for maximum unit capacity and minimum
pressure drop. Complete the refrigerant piping from indoor

LEGEND
TXV — Thermostatic Expansion Valve

Fig. 5 — Location of Sight Glass(es)
and Filter Driers

—7—

Table 4 — Refrigerant Specialties Part Numbers
LIQUID LINE
SIZE
1/ ″
2
5/ ″
8
3/ ″
8
1/ ″
2
1/ ″
2
5/ ″
8
3/ ″
4

UNIT
575B072
575C090
575C120
541A180

LIQUID LINE
SOLENOID VALVE (LLSV)
200RB GS-1928 5T4
200RB GS-1929 5T5
200RB GS-1928 5T4†
200RB GS-1928 5T4
200RB GS-1928 5T4
**
**

LLSV COIL

SIGHT GLASS

FILTER DRIER

AMG-24/50-60
AMG-24/50-60
AMG-24/50-60
AMG-24/50-60
AMG-24/50-60
**
**

AMI1TT4
AMI1TT5
AMI1TT3
AMI1TT4
AMI1TT4
AMI1TT5
AMI1TT5

*
*
P504-8083S
P504-8084S
P504-8164S
P504-8085S Qty 2
P504-8085S Qty 2

*A filter drier is shipped loose with the 575B072 units.
†Bushings required.
**Factory Installed.

F. Provide Safety Relief
A fusible plug is located on the compressor crankcase or in
the liquid line. See Fig. 6. Do not cap this plug. If local code
requires additional safety devices, install them as directed.
Head Pressure Control (541A180 only)
Fan cycling for head pressure control is a standard offering
but is functional on the cooling cycle only. Number 2 fan
cycles as a function of liquid pressure. Fan cycling pressure
switch cycles the fan off at 160 ± 10 psig as pressure
decreases and cycles back on at 255 ± 10 psig. Switch is automatically bypassed in heating cycle. Table 5 shows minimum
outdoor air temperature for full cooling capacity.

Fig. 6 — Location of Fusible Plug —
541A180 Unit

G. Vapor Line Piping Procedure
Connect system vapor line to the vapor line stub on the outdoor unit and the vapor stubs on the indoor unit. At the
indoor unit, construct vapor piping branches as shown in
Fig. 7 for good mixing of the refrigerant leaving the indoor
coil during cooling. This will ensure proper TXV (thermostatic expansion valve) bulb sensing.
Where vapor line is exposed to outdoor air, line must be insulated. See Table 6 for insulation requirements.
Table 5 — Minimum Outdoor Air
Operating Temperature
UNIT
575B
575C
541A

072
090
120
180

MINIMUM OUTDOOR TEMP — F*
%
COMPRESSOR
Standard
Head Pressure
CAPACITY
Unit
Control†
0
0
100
35
–20
35
–20
100
23
–20
67
36
–20

*Applies to Cooling mode of operation only.
†Wind baffles (field-supplied and field-installed) are recommended for
all units with low ambient head pressure control. Refer to Low Ambient
Control Installation Instructions (shipped with accessory) for details.
LEGEND
TXV — Thermostatic Expansion Valve

Table 6 — Insulation for Vapor Line Exposed
to Outdoor Conditions
LENGTH OF EXPOSED
VAPOR LINE*
ft
10

Fig. 7 — Vapor Line Branch Piping Details
INSULATION THICKNESS†
in.
3/ 8

1/ 2

3/ 4

*Recommended vapor line insulation for piping exposed to outdoor
conditions to prevent loss of heating during heating cycle. When vapor
line goes through interior spaces, insulation should be selected to prevent condensation on cooling cycle. Heating capacity should be
reduced 1000 Btuh if over 35 ft of vapor line with 3/4 in. insulation is
exposed to outdoor conditions.
†Closed cell foam insulation with a thermal conductivity of: 0.28 Btu
• in./ft2 • h • °F.

—8 —

IV. COMPLETE ELECTRICAL CONNECTIONS
A. Power Supply
Electrical characteristics of available power supply must
agree with nameplate rating. Supply voltage must be within
tolerances shown in Table 7. Phase imbalance must not
exceed 2%. Operation of unit on improper supply voltage or
with excessive phase imbalance constitutes abuse and is not
covered by Bryant warranty.

IMPORTANT: Operation of unit on improper power supply
voltage or with excessive phase imbalance constitutes abuse
and is not covered by Bryant warranty.
D. General Wiring Notes (See Fig. 8-13)
1. A crankcase heater is wired in the control circuit so it
is always operable as long as power supply disconnect
is on, even if any safety device is open or unit stop/
start switch is off.
2. The power-circuit field supply disconnect should
never be open except when unit is being serviced or is
to be down for a prolonged period. When operation is
resumed, crankcase heater should be energized for
24 hours before start-up. If system is to be shut down
for a prolonged period, it is recommended that the
suction and discharge valves be closed to prevent
an excessive accumulation of refrigerant in the compressor oil.
3. Terminals for field power supply are suitable for copper, copper-clad aluminum, or aluminum conductors.
4. Bryant recommends an indoor airflow switch (field
supplied) be installed and interlocked with the
outdoor unit. This prevents the outdoor unit from
operating if indoor airflow fails (broken fan belt, etc.).
Operation of the compressor in vacuum can damage
bearing surfaces. Install indoor airflow switch in a
convenient location at the indoor supply air duct and
wire per Fig. 14.
5. If the system is equipped with an accessory electric
heater, refer to the 524A-H installation instructions
and tables.

Per local code requirements, provide an adequate fused
disconnect switch within sight of unit and out of reach of
children. Provision the switch for locking open (off) to
prevent power from being turned on while unit is being
serviced. The disconnect switch, fuses, and field wiring must
comply with local requirements. Refer to Table 7 for unit
electrical data.
B. Power Wiring
All power wiring must comply with applicable local requirements. Run power wires from disconnect switch through unit
power opening and connect to terminal block inside the unit
control box. Unit must be grounded.
C. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply
voltage is greater than 2%. Use the following formula to
determine the percentage of voltage imbalance:
% Voltage Imbalance:
max voltage deviation from average voltage
= 100 x
average voltage
Example: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v
452 + 464 + 455
Average Voltage =
3
1371
=
3
= 457
(AB) 457 – 452 = 5 v
(BC) 464 – 457 = 7 v
(AC) 457 – 455 = 2 v
Maximum deviation is 7 v.
Determine percent of voltage imbalance.
% Voltage Imbalance= 100 x 7
457
= 1.53%
This amount of phase imbalance is satisfactory as it is below
the maximum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance is
more than 2%, contact your local electric utility company
immediately.
WARNING: Unit cabinet must have an uninterrupted, unbroken electrical ground to minimize the
possibility of personal injury if an electrical fault
should occur. This ground may consist of electrical wire
connected to unit ground lug in control compartment,
or conduit approved for electrical ground when
installed in accordance with NEC (National Electrical
Code), ANSI/NFPA (American National Standards
Institute/National Fire Protection Association), and
local electrical codes. Failure to follow this warning
could result in the installer being liable for personal
injury of others.

E. Control Circuit Wiring
Control voltage is 24 v. See unit label diagram for field
supplied wiring details. Route control wires through opening
in unit to connection in unit control box.
Control Transformer Wiring
On 208/230V units, check the transformer primary wiring
connections. See Fig. 8 or refer to unit label diagram.
For 575B,C Unit — If unit will be operating at 208-3-60
power, remove black wire (BLK) from the transformer primary connection labeled “230” and move it to the connection
labeled “208”. See Fig. 8.
For 541A Unit — Transformers no. 1 and 2 are wired for a
230-v unit. If a 208/230-v unit is to be run with a 208-v
power supply, the transformers must be rewired as follows:
1. Remove cap from red (208 v) wire.
2. Remove cap from orange (230 v) spliced wire.
3. Replace orange wire with red wire.
4. Recap both wires.
IMPORTANT: BE CERTAIN UNUSED WIRES ARE
CAPPED. Failure to do so may result in damage to the
transformer.

—9—

Duplex 575C120, 541A180 with 524A-H240 or 524A-H300
In order to properly connect two heat pump condensing
units to a single 524A-H packaged air handler, it is
necessary to add field-supplied Fan Coil Relay Board(s),
P/N 33ZCRLYBRD. Relay board(s) no. 1 and no. 2 should be
installed in the control box of condensing unit.
IMPORTANT: The common (COM) terminals from the fan
coil relay board(s) must be connected to the ‘C’ terminal in
condensing unit ‘A’.
Route thermostat cable or equivalent single leads of
no. 18 AWG (American Wire Gage) colored wire from subbase terminals through conduit in unit to low-voltage connections as shown on unit wiring diagram and Fig. 12
and 13.

Fig. 8 — Wiring Diagram — 575C090,120 —
Control Transformer

NOTE: For wire runs up to 50 ft, use no. 18 AWG insulated wire
(35 C minimum). For 51 to 75 ft, use no. 16 AWG insulated
wire (35 C minimum). For over 75 ft, use no. 14 AWG insulated
wire (35 C minimum). All wire larger than no. 18 AWG cannot
be directly connected to the thermostat and will require a junction box and a splice at the thermostat.

Table 7 — Electrical Data
UNIT

575B

072

090

575C
120

541A

FLA
LRA
MCA
MOCP
NEC
RLA

180

—
—
—
—
—
—

FACTORYINSTALLED
OPTION

NOMINAL VOLTAGE
(V-Ph-Hz)

NONE

VOLTAGE RANGE*

COMPRESSOR

FAN MOTORS

POWER SUPPLY

Min

Max

RLA

LRA

FLA

MCA

MOCP

208/230-3-60
460-3-60
575-3-60

187
414
517

253
506
633

18.9
9.5
7.6

146
73
58

5.1
2.6
1.2

208/230-3-60

187

254

29.0

190

1.5

28.7
14.5
10.7
39.0
43.8
19.8
21.9
45.0
50.0
23.0
25.0
18.0
20.0
87.5
40.7
33.0

45
20
15
60
60
30
30
60
70
30
30
25
25
125
60
50

NONE OR DISCONNECT
CONVENIENCE OUTLET
NONE OR DISCONNECT
CONVENIENCE OUTLET
NONE OR DISCONNECT
CONVENIENCE OUTLET
NONE OR DISCONNECT
CONVENIENCE OUTLET
NONE OR DISCONNECT
CONVENIENCE OUTLET

460-3-60

418

506

15.0

0.7

208/230-3-60

187

254

34.0

225

1.5

460-3-60

418

506

17.0

114

0.7

575-3-60

523

632

14.0

0.7

NONE

208/230-3-60
460-3-60
575-3-60

187
414
518

253
528
660

63.6
29.3
23.8

266
120
96

4.3
2.3
1.8

LEGEND
Full Load Amps
Locked Rotor Amps
Minimum Circuit Amps
Maximum Overcurrent Protection
National Electrical Code
Rated Load Amps

NOTES:
1. The MCA and MOCP values are calculated in accordance with the
NEC, Article 440.
2. Motor RLA and LRA values are established in accordance with
Underwriters’ Laboratories (UL), Standard 1995.
3. The 575-v units are UL, Canada-listed only.
4. Convenience outlet is available as either a factory-installed option
or a field-installed accessory and is 115-v, 1 ph, 60 Hz.

*Units are suitable for use on electrical systems where voltage supplied
to the unit terminals is not below or above the listed limits.

—10—

FAN

DF
LP/HP
PS
RV
SEN
TSTAT

DEFROST Y-RV
CONTROL
BK RV
BK COIL

BL
BL

PS2
PS1

Y
BK
BK

DF
R C

LP/HP

SEN

O Y W

R-RV

DEFROST HEAT
COMPRESSOR
HEAT/COOL

Y
O
BL

FROM
TSTAT

NOTES:
1. All electrical work must be done in conformance with the National
Electrical Code (NFPA No. 70) and in conformance with local
codes and authorities having jurisdiction.
2. For use with copper conductors only.

COMMON
24 VAC

LEGEND
Defrost Relay
Low or High-Pressure Switch (Optional)
Pressure Switch
Reversing Valve
Outdoor Coil Temperature Sensor
Thermostat
Line Voltage Factory
Low Voltage Factory
Low Voltage Field

COLOR CODE
BK Black
BL Blue
O
Orange
R
Red
W White
Y
Yellow

LP/HP

—
—
—
—
—
—

CAUTION: Not suitable for use on systems exceeding
150 volts to ground.

Fig. 9 — Wiring Diagram — 575B072; 208/230-3-60 Units

THERMOSTAT

CONNECTION
BOARD (TB)

IFC

LLSV

LEGEND
IFC — Indoor Fan Contactor
LLSV — Liquid Line Solenoid Valve
TB
— Terminal Block
Field Wiring
NOTES:
1. For thermostat and subbase part no. see
price pages.
2. Use copper conductors only.

TO ELECTRIC
HEATER
ACCESSORY,
IF EQUIPPED

Fig. 10 — Wiring Diagram — 575C090,120; 230-3-60 Units

—11—

EQUIP
GND
HC
IFC
IFM
NEC
TB

—
—
—
—
—
—
—

LEGEND
Equipment
Ground
Heater Contactor
Indoor Fan Contactor
Indoor Fan Motor
National Electrical Code
Terminal Block

Fig. 11 — Wiring Diagram — 541A180 Unit With Standard Thermostat and Electric Heat

—12—

TB1
DISCONNECT

FIELD
POWER
SUPPLY

3-Ph ONLY

HC1

L1
L2

HTR1

HC1

EQUIP GND
CIRCUIT BREAKER
(5 HP AND LARGER)
IFC

11
12
13

524A-H240
TERMINAL BLOCK
TB1
FIELD POWER
R
WIRING

21 BLK
22 BLK
23 BLK

1
2
3

IFM

UNIT WIRING

524A-H
HEAT ACCESSORY

Y1
Y2

HEAT PUMP “A”
W1

W1
W2
G

WHT C1 IFC C2

WHT

W2
C

TB2
R

CR
R

RELAY BOARD
(33ZCRLYBRD)

Y1
Y2

W2
W2

G
C
CR

G3/(Y)
COM

G
C

TSTAT

HEAT PUMP “B”

CR
EQUIP
GND
HC
HTR
IFC
IFM
TB
TSTAT

—
—
—
—
—
—
—
—
—

FAN

G2/(W)

LEGEND
Control Relay (Field-Supplied)
Equipment
Ground
Heating Contactor
Electric Heater
Indoor-Fan Contactor
Indoor-Fan Motor
Terminal Block
Thermostat
Factory Wiring

TB2
R
Y1
Y2
W1
W2

Field Control Wiring
G

NOTE: Use copper conductors only.

C
X

Fig. 12 — Wiring Diagram — Duplex 575C120 With 524A-H240 and Electric Heat

—13—

(VALVE)
HI(COOL)
MED(HEAT)
LO

DISCONNECT

FIELD
POWER
SUPPLY

3-Ph ONLY

TB1

HC1

L1
L2

HTR1

HC1

EQUIP GND
CIRCUIT BREAKER
(5 HP AND LARGER)
IFC

11
12
13

524A-H300
TERMINAL BLOCK
TB1
FIELD POWER
R
WIRING

21 BLK
22 BLK
23 BLK

1
2
3

IFM

UNIT WIRING

524A-H
HEAT ACCESSORY

Y1
Y2

HEAT PUMP A
541A180

W1
W2
G

WHT C1 IFC C2

WHT

W2
C

TB2
R
RELAY BOARD
(33ZCRLYBRD)

G2/(W)

W1
W2

G3/(Y)

COM

RELAY BOARD
(33ZCRLYBRD)

B
W1

FAN

(VALVE)

HI(COOL)

MED(HEAT)

FAN

G2/(W)

G3/(Y)
COM

(VALVE)
HI(COOL)
MED(HEAT)
LO

TSTAT*

1
2

CR
EQUIP
GND
HC
HTR
IFC
IFM
TB
TSTAT

—
—
—
—
—
—
—
—
—

HEAT PUMP B
575C120

LEGEND
Control Relay (Field-Supplied)
Equipment
Ground
Heating Contactor
Electric Heater
Indoor-Fan Contactor
Indoor-Fan Motor
Terminal Block
Thermostat
Factory Wiring

TB2

R
Y1
Y2
W1

W2
G

Field Control Wiring

*Do not configure TSTAT for heat pump.
NOTE: Use copper conductors only.

Fig. 13 — Wiring Diagram — Duplex 575C120 and 541A180 With 524A-H300 and Electric Heat

LEGEND
AFS — Airflow Switch (Sail Switch)
CR — Control Relay
DB — Defrost Board
Factory Wiring
Field Control Wiring
NOTES:
1. Locate YEL wire between Y on DB and terminal 5 of CR3
and cut.
2. Splice airflow switch (AFS) (field supplied) contact wires (field
provided) to two ends of cut YEL wire as depicted.

Fig. 14 — Typical Field Wiring for Airflow Switch —
541A180/524A-H

—14—

PRE-START-UP
IMPORTANT: Before beginning Pre-Start-Up or Start-Up,
review Start-Up Checklist at the back of this book. The
checklist assures proper start-up of the system and provides
a record of unit condition, application requirements, system
information, and operation at initial start-up.

SNUBBER WASHER

SELF-LOCKING
BOLT

NEOPRENE
SNUBBER

COMPRESSOR FOOT

CAUTION: Do not attempt to start the heat pump
system, even momentarily, until the following steps
have been completed. Compressor damage may result.

Fig. 15A — Compressor Mounting — 575B072 and
575C090,120 Units

I. PRELIMINARY CHECKS
1. Check all air handler and other equipment auxiliary
components. Consult manufacturer’s instructions regarding any other equipment attached to unit. If unit
has field-installed accessories, be sure all are properly
installed and correctly wired. If used, airflow switch
must be properly installed. See Fig. 14 for typical field
wiring.
2. As shipped, compressor is held down by 4 bolts. After
unit is installed, loosen each bolt and locknut until
flat washer or snubber can be moved with finger pressure. Be sure compressor floats freely on the mounting springs (541A units only). See Fig. 15A and 15B
for compressor mounting.
3. Check tightness of all electrical connections.
4. Electrical power source must agree with nameplate
rating.
5. Turn on crankcase heater for 24 hours before starting
the unit to be sure all refrigerant is out of the oil. To
energize crankcase heater, perform the following steps:
a. Set the space thermostat system switch to OFF, or
adjust the temperature so there is no demand for
cooling.
b. Close the field disconnect.

Fig. 15B — Compressor Mounting — 541A180 Units

150 PSI MAX

DRY
NITROGEN

c. Leave the compressor circuit breaker off. The
crankcase heater is now energized.

LIQUID LINE
SOLENOID VALVE
SUCTION LINE

6. Leak test the field refrigerant piping, connections
and joints, and indoor coil. To perform leak test, complete the following steps:
a. Pressurize refrigerant piping; do not exceed
150 psi.
b. Using soap bubbles and/or an electronic leak
detector, test refrigerant piping, connections and
joints, and the indoor coil. See Fig. 16.

OUTDOOR
UNIT

TXV

LIQUID LINE

SOAP

→ Fig. 16 — Recommended Process for
Checking for Leaks

c. Check for leaks.
Evacuate and dehydrate entire refrigerant system.
7. 541A180 only — compressor oil level should be visible
in sight glass. Adjust the oil level as required. No oil
should be removed unless the crankcase heater has
been energized for at least 24 hours. See Start-Up
section, Preliminary Oil Charge.
NOTE: The 575B, 575C units do not have a compressor oil level sight glass. These units are factory
charged with the required amount of oil. If required,
use the following oil for replacement: For 575B units
use Zerol 150, part number P903-2001. For 575C
units use RCD, part number P903-0101.
8. Backseat (open) compressor suction and discharge
valves. Now close valves one turn to allow refrigerant
pressure to reach test gages.

INDOOR
COIL

II. PRELIMINARY CHARGE

—15—

CAUTION: The 575C090 and 575C120 units contain a
9 lb charge of refrigerant. Add remainder of preliminary
charge and allow pressure to equalize before starting
compressor. Failure to do so WILL cause the compressor to
overheat in a few minutes, possibly causing permanent
compressor damage. The amount of refrigerant added
must be at least 80% of the operating charge listed in
the Physical Data table (Table 1).

Before starting the unit, charge liquid refrigerant into the
high side of the system through the liquid service valve.
Allow high and low side pressures to equalize before starting
compressor. If pressures do not equalize readily, charge
vapor on low side of system to assure charge in the evaporator. Refer to GTAC II, Module 5, Charging, Recovery, Recycling, and Reclamation for liquid charging procedures.
III. LIQUID LINE SOLENOID
To minimize refrigerant migration to the compressor during
the heat pump OFF cycle, the 575B,C unit must have a
bi-flow liquid line solenoid valve (field supplied). The valve
opens when the compressor is energized, and closes when
the compressor is deenergized. This reduces compressor
flooded starts, thus significantly increasing compressor life.
IV. ACCUMULATOR
The unit accumulator controls the rate of liquid refrigerant
to the compressor during heat pump operation.
The 541A accumulator features a unique method for
returning oil to the compressor. The oil return mechanism is
external to the accumulator. The mixture of oil and refrigerant is metered to the compressor by a brass orifice which is
removable and cleanable. The oil return mechanism also
contains a solenoid valve that opens when the compressor is
ON and closes when the compressor is OFF. This keeps the
liquid refrigerant stored in the accumulator from draining to
the compressor during the heat pump OFF cycle, which
further protects the compressor against flooded starts.

becomes excessive, and automatically resets when the
internal temperature drops to a safe level. This overload
usually resets within 60 minutes (or longer). If the internal
overload is suspected of being open, disconnect the electrical
power to the unit and check the circuit through the overload
with an ohmmeter or continuity tester.
III. ADVANCED SCROLL TEMPERATURE PROTECTION
(ASTP)
Advanced Scroll Temperature Protection (ASTP) is a form of
internal discharge temperature protection that unloads the
scroll compressor when the internal temperature reaches
approximately 300 F. At this temperature, an internal bimetal disk valve opens and causes the scroll elements to separate, which stops compression. Suction and discharge pressures balance while the motor continues to run. The longer
the compressor runs unloaded, the longer it must cool before
the bi-metal disk resets. See Fig. 17.
To manually reset ASTP, the compressor should be stopped
and allowed to cool. If the compressor is not stopped, the
motor will run until the motor protector trips, which occurs
up to 90 minutes later. Advanced Scroll Temperature Protection will reset automatically before the motor protector
resets, which may take up to 2 hours. A label located above
the terminal box identifies Copeland Scroll compressor
models (ZR94, 108 and 125) that contain this technology. See
Fig. 18.

START-UP

Recommended Cooling Time
(Minutes)

CAUTION: Compressor crankcase heater must be
on for 24 hours before start-up. After the heater has
been on for 24 hours, the unit can be started.

CAUTION: Prior to starting compressor, a preliminary
charge of refrigerant must be added to avoid possible
compressor damage.
I. COMPRESSOR ROTATION (575B,C Units)

120
110
100
90
80
70
60
50
40
30
20
10
0
0

On 3-phase units with scroll compressors, it is important to
be certain compressor is rotating in the proper direction. To
determine whether or not compressor is rotating in the
proper direction:
1. Connect service gages to suction and discharge pressure fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge
pressure should rise, as is normal on any start-up.
If the suction pressure does not drop and the discharge
pressure does not rise to normal levels:
1. Note that the condenser fan is probably also rotating
in the wrong direction.
2. Turn off power to the unit, tag disconnect.

Compressor Unloaded Run Time (Minutes)

*Times are approximate.
NOTE: Various factors, including high humidity, high ambient temperature, and the presence of a sound blanket will increase cool-down
times.

Fig. 17 — Recommended Minimum Cool-Down Time After
Compressor is Stopped*

3. Reverse any two of the unit power leads.
4. Reapply power to the compressor, verify correct
pressures.
The suction and discharge pressure levels should now move
to their normal start-up levels.
II. COMPRESSOR OVERLOAD
This overload interrupts power to the compressor when
either the current or internal motor winding temperature

—16—

Fig. 18 — Advanced Scroll Temperature Protection Label

IV. COMPRESSOR LOCKOUT DEVICE
The compressor lockout (CLO) device prevents the compressor from starting or running in a high pressure, loss-ofcharge or freezestat open situation. Reset the CLO device by
setting the thermostat to eliminate cooling demand and
return it to the original set point. If the system shuts down
again for the same fault, determine the possible cause before
attempting to reset the CLO device.
V. PRELIMINARY OIL CHARGE (541A)
The compressor is factory charged with oil (see Table 1).
When oil is checked at start-up, it may be necessary to add or
remove oil to bring it to the proper level. Add oil only if
necessary to bring oil into view in sight glass. Use only
Bryant-approved compressor oil. One recommended oil
level adjustment method is as follows:
A. Add Oil
Close suction service valve and pump down crankcase to
2 psig. Wait a few minutes and repeat until pressure remains
steady at 2 psig. Remove oil fill plug above the sight glass,
add oil through plug hole, and replace plug. Run compressor
for 20 minutes and check oil level.
NOTE: Use only Bryant-approved compressor oil. Approved
sources are:

Refer to Charging Charts Fig. 19A-19C and Table 8. Do not
exceed maximum refrigerant charge. Vary refrigerant until
the conditions of the chart are met. Note that charging
charts are different from type normally used. Charts are
based on charging the units to the correct subcooling for the
various operating conditions. Accurate pressure gage and
temperature sensing device are required.
Connect the pressure gage to the service port on the liquid
line service valve. Mount the temperature sensing device
on the liquid line, close to the liquid line service valve and
insulate it so that outdoor ambient temperature does not
affect the reading. Indoor airflow must be within the normal
operating range of the unit. Operate unit a minimum of
15 minutes. Ensure pressure and temperature readings have
stabilized. Plot liquid pressure and temperature on chart
and add or reduce charge to meet curve. Adjust charge to
conform with charging chart, using the liquid pressure and
temperature to read chart.
If the sight glass is cloudy, check refrigerant charge again.
Ensure all fans are operating. Also ensure maximum allowable liquid lift has not been exceeded. If charged per chart
and if the sight glass is still cloudy, check for a plugged filter
drier or a partially closed solenoid valve. Replace or repair,
as needed.

Petroleum Specialties, Inc.. . . . . . . . . . . . . . . . . . . Cryol 150A
Texaco, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Capella WF-32
Witco Chemical Co.. . . . . . . . . . . . . . . . . . . . . . . . .Suniso 3GS
Do not use oil that has been drained out, or oil that has been
exposed to atmosphere.

VIII. CHECK HEATING CYCLE OPERATION
Place thermostat selector switch at HEAT and reset the
space set point above ambient temperature so that a call for
heating is ensured. Compressor will start within 5 minutes.
Observe system operation.

B. Remove Oil
Pump down compressor to 2 psig. Loosen the 1/4-in. pipe plug
at the compressor base and allow the oil to seep out past the
threads of the plug. Retighten plug when level is correct.

IX. CHECK COMPRESSOR OIL LEVEL (541A)
After adjusting the refrigerant charge, allow the system to
run fully loaded for 20 minutes. Running oil level should be
within view in the crankcase sight glass. Stop compressor at
the field power supply disconnect and check the crankcase
oil level. Add oil only if necessary to bring the oil into view in
the sight glass. If oil is added, run the system for an additional 10 minutes, then stop and check oil level. If the level
remains low, check the piping system for proper design for oil
return; also check the system for leaks.

NOTE: The crankcase is slightly pressurized. Do not remove
the plug, or the entire oil charge will be lost.
Small amounts of oil can be removed through the oil pump
discharge connection while the compressor is running.
VI. START UNIT
The field disconnect is closed, the fan circuit breaker is
closed, and the space thermostat is set above ambient so that
there is no demand for cooling. Only the crankcase heater
will be energized.
Next, close the compressor circuit breaker and then reset
space thermostat below ambient so that a call for cooling is
ensured.

If the initial check shows too much oil (too high in the sight
glass) remove oil to proper level. See Preliminary Oil Charge
section for proper procedure for adding and removing oil.
When the above checks are complete, repeat the procedure
with the unit operating at minimum load conditions. Unload
the compressor by disconnecting the field-control circuit lead
at TB2 Y2 .

NOTE: Do not use circuit breaker to start and stop the compressor except in an emergency.

Reconnect the field-control circuit lead when checks are
complete.

After starting, there is a delay of at least 3 seconds before
compressor starts.

X. FINAL CHECKS

VII. ADJUST REFRIGERANT CHARGE

Ensure all safety controls are operating, control panel covers
are on, and the service panels are in place.

CAUTION: Never charge liquid into the lowpressure side of system. Do not overcharge. During
charging or removal of refrigerant, be sure indoor-fan
system is operating.

Table 8 — Maximum Refrigerant Charge
UNIT
575B
575C

CAUTION: Charge unit on cooling cycle only. If
unit is charged on heating cycle, overcharging may
occur.

541A

—17—

072
090
120
180

R-22
(lb)
27.0
34.2
34.2
62.0

SEQUENCE OF OPERATION
I. 575B072 UNITS
When power is supplied to unit, the transformer (TRAN) and
crankcase heater (CCH) are energized.
A. Cooling
On a call for cooling, the thermostat completes the following
circuits: R-G, R-Y, and R-O. If the compressor recycle delay of
3 minutes is complete, the compressor and outdoor fan start.
The reversing valve is energized for cooling and the indoorfan motor starts.
When the thermostat is satisfied, the circuits are opened,
and the compressor, outdoor-fan motor, and indoor-fan motor
stop. The reversing valve is deenergized.
B. Heating
On a call for heating, the thermostat completes the following
circuits: R-G and R-Y. If the compressor recycle delay of
3 minutes is complete, the compressor and outdoor fan start.
The indoor-fan motor will also start.
If room temperature continues to fall, the thermostat
completes circuit R-W. If the optional electric heat package is
used, the heat relay is energized, and the electric heaters are
energized.

140

130

49
43
38
32
27
21

LIQUID TEMPERATURE AT LIQUID VALVE (F)

LIQUID TEMPERATURE AT LIQUID VALVE (C)

Fig. 19A — 575B072 Charging Chart

When the thermostat is satisfied, the circuits are opened,
and the compressor, outdoor-fan motor, heaters, and indoorfan motor stop.

ADD CHARGE IF ABOVE CURVE
120

C. Defrost
Defrost board (DB) is a time and temperature control, which
includes a field-selectable time period between checks for
frost (30, 50, and 90 minutes). Electronic timer and defrost
cycle start only when contactor is energized and defrost thermostat (DFT) is closed (below 28 F).

110
100
90
80

Defrost mode is identical to Cooling mode, except outdoor-fan
motor (OFM) stops and a bank of supplemental electric heat
turns on to warm air supplying the conditioned space.
Defrost mode is terminated when the DFT reaches 65 F.

70
REDUCE CHARGE IF BELOW CURVE

50
50

100

344

689

150
200
250
300
LIQUID PRESSURE AT LIQUID VALVE (PSIG)
1034
2069
1379
1724
LIQUID PRESSURE AT LIQUID VALVE (Kilopascals)

Fig. 19B — 575C090,120 Charging Chart

350
2414

400

D. Air Circulation
When the fan switch is at FAN ON, the indoor-air fans operate continuously to provide ventilation. The thermostat
operates the other components as described above.
E. Emergency Heat Cycle
If the compressor is inoperative due to a tripped safety
device, the second stage of the thermostat automatically
energizes the indoor-air fan and the electric resistance heaters (if equipped).
II. 575C090,120 UNITS
When power is supplied to unit, the transformer (TRAN) is
energized. The crankcase heater is also energized.
A. Cooling
With the thermostat subbase in the cooling position, and
when the space temperature comes within 2° F of the cooling
set point, the thermostat makes circuit R-O. This energizes
the reversing valve solenoid (RVS) and places the unit in
standby condition for cooling.
As the space temperature continues to rise, the second stage
of the thermostat makes, closing circuit R-Y. When compressor time delay (5 ± 2 minutes) is completed, a circuit is made
to contactor (C), starting the compressor (COMP) and
outdoor-fan motor (OFM). Circuit R-G is made at the same
time, energizing the indoor-fan contactor (IFC) and starting
the indoor-fan motor (IFM) after one-second delay.

Fig. 19C — 541A180 Charging Chart

—18—

When the thermostat is satisfied, contacts open, deenergizing C. The COMP, IFM, and OFM stop.

When the thermostat is satisfied, the contacts open, deenergizing first the Heat Pump B and then Heat Pump A.

B. Heating
On a call for heat, thermostat makes circuits R-Y and R-G.
When compressor time delay (5 ± 2 minutes) is completed, a
circuit is made to C, starting COMP and OFM. Circuit R-G
also energizes IFC and starts IFM after a 1-second delay.

Heating
When the thermostat calls for heating, the circuit from R to
Y1 is completed. If the time delays and safeties are satisfied,
the compressor contactor closes, starting the compressor and
outdoor-fan motors of Heat Pump A and Heat Pump B. At
the same time the circuit is completed from R to G, starting
the indoor-fan motor. If the second stage of heating is
required, the circuit from R to W2 will be completed and the
electric resistance heaters will be energized.
When the thermostat is satisfied, the contacts open, deenergizing Heat Pump A and Heat Pump B.

III. 541A180 UNITS
A. Heating
Place thermostat selector at HEAT and set temperature
selector above room ambient.
B. Cooling
Place thermostat selector at COOL and set temperature
selector below room ambient.
When thermostat calls for unit operation (either heating or
cooling), the indoor-fan motor starts immediately. The
outdoor-fan motors and compressor start within 3 seconds to
5 minutes depending on when unit was last shut off by thermostat, because unit contains a compressor time delay circuit. When first-stage cooling is required, thermostat (TC1)
closes, causing the heat pump to start with an unloaded compressor. When TC2 closes, demanding additional cooling, the
compressor loads to full load operation.
During heating, compressor is always fully loaded. When
TH1 demands first-stage heating, the heat pump starts
within 3 seconds to 5 minutes depending on when unit was
last shut off by thermostat, because unit contains a compressor time delay circuit. (The defrost board has speed terminals to shorten this cycle.) When TH2 of the thermostat
closes, auxiliary heat supply (electric strip heat) is energized
in 1 or 2 stages depending on number of stages available and
whether outdoor thermostats are closed.
Defrost is achieved by reversal from heating to cooling cycle
and deenergization of outdoor-fan motors, allowing hot
refrigerant gas to defrost outdoor coil. Defrost is achieved
with a timer set to initiate defrost every 30, 50, or
90 minutes (factory set at 30 minutes).
Defrost is initiated when refrigerant temperature leaving
the outdoor coil is measured below 27 F, (typically when the
outdoor ambient temperature is below 45 F as sensed by the
defrost thermostat [DFT]).
Defrost is terminated when: The refrigerant temperature
rises to 80 F at the DFT location on the liquid line; or the
refrigerant pressure rises to 280 psig at the HPS2 location
on the liquid line; or the defrost timer completes the
10-minute cycle.
IV. DUPLEX UNITS
A. Duplex 575C120 Units with 524A-H240 (See Fig. 12)
Cooling
When the thermostat is set for cooling, and the space temperature comes within 2° F of the cooling set point, the thermostat completes the circuit from R to O and the reversing
valves in both units are energized. If the space temperature
continues to rise, the circuit from R to Y1 is completed. If the
time delays and safeties are satisfied, the compressor contactor closes, starting the compressor and outdoor-fan motors of
Heat Pump A. At the same time the circuit is completed from
R to G, starting the indoor-fan motor. If the space temperature continues to rise, the circuit is completed from R to
Y2 and the Cooling mode is initiated in Heat Pump B in a
similar manner.

B. Duplex 575C120 and 541A180 Units With 524A-H300
(See Fig. 13)
Cooling
When the thermostat calls for cooling, the circuit from R to
Y1 is completed. If the time delays and safeties are satisfied,
the compressor contactor closes, starting the compressor and
outdoor-fan motors of Heat Pump A (541A180). At the same
time the circuit is completed from R to G, starting the indoorfan motor. If the space temperature continues to rise, the
circuit is completed from R to Y2 and the Cooling mode is
initiated in Heat Pump B (575C120).
When the thermostat is satisfied, the contacts open, deenergizing first the Heat Pump B and then Heat Pump A.
Heating
When the thermostat calls for heating, the circuit from R to
W1 is completed. If the time delays and safeties are satisfied,
the compressor contactor closes, starting the compressor and
outdoor-fan motors of Heat Pump A and Heat Pump B. At
the same time the circuit is completed from R to G, starting
the indoor-fan motor. If the second stage of heating is
required, the circuit from R to W2 will be completed and the
electric resistance heaters will be energized.
When the thermostat is satisfied, the contacts open, deenergizing Heat Pump A and Heat Pump B.
C. Safeties
The high-pressure switch, loss-of-charge switch, oil pressure
safety switch, and compressor overtemperature safety are
located in a CLO circuit that prevents heat pump operation
if these safety devices are activated. A light at the thermostat energizes when CLO circuit is affected. The lockout system can be reset by adjusting the thermostat to open the
contacts (down for Heating mode, up for Cooling mode),
deenergizing the CLO circuitry. Compressor overcurrent protection is achieved with a circuit breaker which requires
manual resetting at the outdoor unit control box.
The unit is equipped with an oil pressure safety switch that
protects the compressor if oil pressure does not develop on
start-up or is lost during operation. The oil pressure switch
is of the manual reset type and therefore must be reset at
the outdoor unit. DO NOT RESET MORE THAN ONCE.
If oil pressure switch trips, determine cause and correct. DO
NOT JUMPER OIL PRESSURE SAFETY SWITCH.
To reset the oil pressure switch:
1. Disconnect power to the unit.

—19—

2. Press the RESET button on the oil pressure switch.
3. Reconnect power to the unit.

6. Remove or disconnect crankcase heater from compressor base.

Unit is equipped with a no-dump reversing valve circuit.
When unit is in Cooling mode, reversing valve remains in
cooling position until a call for heating is requested by thermostat. When unit is in Heating mode, reversing valve
remains in heating position until there is a call for cooling.
The crankcase heater is in a lockout circuit. If crankcase
heater is defective, compressor is locked off. Heat pump
remains off until corrective action is taken. The lockout circuit cannot be reactivated by adjusting the thermostat. To
reset the crankcase heater lockout, disconnect and then
reconnect power to unit.

7. Remove compressor from unit.
8. On 541A180 unit remove compressor holddown bolts
and lift compressor off mounting plate.
9. Clean system. Add new liquid line filter drier.
10. Install new compressor on compressor mounting
plate and position in unit. Connect suction and discharge lines to compressor. Secure mounting plate
with compressor to unit. Ensure that compressor
holddown bolts are in place. Connect wiring. Install
crankcase heater.

D. Check Operation
Ensure operation of all safety controls. Replace all service
panels. Be sure that control panel cover is closed tightly.
V. RESTART
Manual reset of the 24-v control circuit is necessary if unit
shutdown is caused by automatic reset devices (including IP
[internal compressor overcurrent protection], HPS [highpressure switch], and LCS [loss-of-charge switch]) or if
shutdown is caused by manual reset devices (including
OPS [oil pressure switch] and compressor circuit breaker
protection). To restart the unit when IP, HPS, or LCS has
tripped (after device has reset automatically), open and then
close the thermostat contacts. Opening and then closing
thermostat contacts interrupts and restores 24-v power to
the compressor lockout (CLO), which resets the circuit.
It is necessary to manually reset the compressor circuit
breaker and OPS at the unit if either of these safeties should
shut down the unit.
IMPORTANT: If OPS trips, it must be reset first before making and breaking the thermostat contacts to reset CLO. If
this procedure is not followed, the CLO cannot reset.
VI. CAUSES OF COMPLETE UNIT SHUTDOWN:
• interruption of supplied power
• open compressor overtemperature protection (IP)
• compressor electrical overload protection (CB)
• open high-pressure or loss-of-charge safety switches
• open oil pressure switch
• open crankcase heater lockout (CLO2)
• open control circuit fuse (FU1 or FU2)
• open discharge gas thermostat (575C only)

11. Evacuate and recharge unit.
12. Restore unit power.
II. 575C090,120 COOLING MODE OPERATION (See Fig. 20)
1. High pressure, high temperature refrigerant vapor
from the compressor flows through the reversing
valve and is directed to the vapor headers of both
outdoor coils.
2. At the outdoor coil vapor header, the high pressure,
high temperature refrigerant vapor flows up to check
valve “A” that blocks the flow. All the refrigerant is
then directed to flow into the coil circuits.
3. Subcooled refrigerant liquid leaves the coil circuits
through the side outlet on the liquid headers. The
liquid refrigerant from each coil flows through check
valves “B” which are open, enters the liquid line and
goes to the indoor coil.
4. The liquid refrigerant is expanded and evaporated in
the indoor coil resulting in low pressure vapor. This
low pressure vapor returns to the outdoor unit
through the system vapor line, reversing valve, and
accumulator, reentering the compressor at the suction connection.
III. 575C090,120 HEATING MODE OPERATION (See Fig. 21)
1. High pressure, high temperature refrigerant vapor
from the compressor flows through the reversing
valve and is directed through the system vapor line to
the indoor coil. Refrigerant is condensed and subcooled in the indoor coil and returns to the outdoor
unit through the system liquid line.

SERVICE
I. COMPRESSOR REMOVAL
See Table 1 for compressor information. Follow safety codes
and wear safety glasses and work gloves.
1. Shut off power to unit. Remove unit access panel.
2. Recover refrigerant from system using refrigerant
recovery methods, and in accordance with local and
national standards.
3. Disconnect compressor wiring at compressor terminal box.
4. Disconnect refrigerant lines from compressor.
5. Remove screws from compressor mounting plate.
CAUTION: Excessive movement of copper lines at
compressor may cause higher levels of vibration when
unit is restored to service.

—20—

2. Check valve “B” blocks the flow of liquid and the
liquid refrigerant must flow through the filter driers,
through check valve “C”, and into the liquid header
assembly.
3. The liquid refrigerant is expanded as it passes
through the fixed orifice metering devices into
outdoor coil circuits. The refrigerant evaporates as it
passes through the coil circuits resulting in low
pressure vapor.
4. The low pressure vapor leaves the coil circuits and
enters the vapor headers, check valves “A” are open,
and returns to the compressor through the vapor line,
reversing valve, and accumulator, reentering the
compressor at the suction connection.

IV. 541A180 COOLING MODE OPERATION (See Fig. 22)
1. High pressure, high temperature refrigerant vapor
from the compressor flows through the reversing
valve and is directed to the outdoor coil vapor header.

3. The liquid refrigerant is expanded as it passes
through the capillary tubes into outdoor coil circuits.
The refrigerant evaporates as it passes through the
coil circuits resulting in low pressure vapor.

2. At the outdoor coil vapor header, the high pressure,
high temperature refrigerant vapor flows up to check
valve “A” that blocks the flow. All the refrigerant is
then directed to flow into the coil circuits.

4. The low pressure vapor leaves the coil circuits and
enters the vapor header, check valve “A” is open, and
returns to the compressor through the vapor line,
reversing valve, and accumulator, reentering the
compressor at the suction connection.

3. Subcooled refrigerant liquid leaves the coil circuits
entering the portion of the vapor header which is
above check valve “A”. Check valve “C” is closed,
therefore, the liquid refrigerant passes through check
valve “B,” which is open, and enters the liquid line
and goes to the indoor coil.
4. The liquid refrigerant is expanded and evaporated in
the indoor coil resulting in low pressure vapor. This
low pressure vapor returns to the outdoor unit
through the system vapor line, reversing valve, and
accumulator, reentering the compressor at the suction connection.
V. 541A180 HEATING MODE OPERATION (See Fig. 23)
1. High pressure, high temperature refrigerant vapor
from the compressor flows through the reversing
valve and is directed through the system vapor line
to the indoor coil. Refrigerant is condensed and
subcooled in the indoor coil and returns to the
outdoor unit through the system liquid line.
2. Check valve “B” blocks the flow of liquid and the
refrigerant is then directed to flow through check
valve “C” (which is open), through the filter drier, and
into the liquid header assembly.

VI. CRANKCASE HEATER
The crankcase heater prevents refrigerant migration and
compressor oil dilution during shutdown when compressor is
not operating.
Close both compressor service valves when crankcase heater
is deenergized for more than 6 hours.
VII. OUTDOOR UNIT FANS
Each fan is supported by a formed-wire mount bolted to the
fan deck and covered with a wire guard. On the 541A180, the
exposed end of the motor shaft is covered with a rubber boot.
In case a fan motor must be repaired or replaced, be sure the
rubber boot is put back on when the fan is reinstalled and be
sure the fan guard is in place before starting the unit.
VIII. LUBRICATION
Fan motors have permanently sealed bearings. No further
lubrication is required.

COMPRESSOR
REVERSING VALVE

VAPOR LINE
BALL
VALVE

ACCUMULATOR

FROM
INDOOR
UNIT

CK VALVE B

CK VALVE A

CK VALVE C

FILTER
DRIER

LIQUID LINE

FIXED ORIFICE
METERING DEVICE

BALL
VALVE

Fig. 20 — 575C090,120 Cooling Mode (Size 090 Shown)

—21—

TO
INDOOR
UNIT

COMPRESSOR
REVERSING VALVE

VAPOR LINE

TO
INDOOR
UNIT

BALL
VALVE

ACCUMULATOR

CK VALVE B

CK VALVE A
CK VALVE C

FILTER
DRIER

LIQUID LINE
FIXED ORIFICE
METERING DEVICE

FROM
INDOOR
UNIT

BALL
VALVE

Fig. 21 — 575C090,120 Heating Mode (Size 090 Shown)

REVERSING
VALVE

REFRIGERANT MIXTURE

MUFFLER
FROM INDOOR
COIL

COMPR
TO INDOOR
COIL

ACCUMULATOR
LIQUID
LLSV
GAS AND OIL

ANGLE
VALVE
WITH SCHRADER
PORT

CK VALVE B

CK VALVE A

HOT GAS

FILTER
DRIER

CK VALVE C
COIL RETURN
BEND END

Fig. 22 — 541A180 Cooling Mode

—22—

REVERSING
VALVE

REFRIGERANT MIXTURE

MUFFLER

TO INDOOR
COIL
COMPR
FROM INDOOR
COIL

ACCUMULATOR
LIQUID
LLSV
GAS AND OIL

ANGLE
VALVE
WITH SCHRADER
PORT

CK VALVE B

CK VALVE A

HOT GAS

FILTER
DRIER

CK VALVE C
COIL RETURN
BEND END

Fig. 23 — 541A180 Heating Mode
IX. COIL CLEANING AND MAINTENANCE

5. Clean the remaining surfaces in the normal manner.

This section discusses the cleaning and the maintenance of
standard coils and E-Coated coils. Routine cleaning of coil
surfaces is essential to minimize contamination build-up and
remove harmful residue. Inspect coils monthly and clean as
required.

6. Reposition outer coil sections. Reinstall clips which
secure tube sheets, and replace top cover and rear
corner posts.
7. Restore unit power.

A. Cleaning Standard Coils
Standard coils can be cleaned with a vacuum cleaner,
washed out with low velocity water, blown out with compressed air, or brushed (do not use wire brush). Fan motors
are dripproof but not waterproof. Do not use acid cleaners.
Clean coil annually or as required by location or outdoor air
conditions. Inspect coil monthly and clean as required. Fins
are not continuous through coil sections. Dirt and debris may
pass through first section and become trapped, restricting
airflow. Use a flashlight to determine if dirt or debris has collected between coil sections.
Clean coils as follows:
1. Turn off unit power.
2. Remove screws holding rear corner posts and top
cover in place. Pivot top cover up 12 to 18 in. and
support with a board or other adequate rigid support.
See Fig. 24.
3. Remove clips securing tube sheets together at the
return bend end of the coil. Carefully spread the ends
of the coil rows apart by moving the outer sections.
See Fig. 25.
4. Using a water hose or other suitable equipment, flush
down between the sections of coil to remove dirt and
debris.

B. Cleaning and Maintaining E-Coated Coils
Routine cleaning of coil surfaces is essential to maintain
proper operation of the unit. Elimination of contamination
and removal of harmful residue will greatly increase the life
of the coil and extend the life of the unit. The following
maintenance and cleaning procedures are recommended as
part of the routine maintenance activities to extend the life
of the coil.
Remove Surface Loaded Fibers
Debris such as dirt and fibers on the surface of the coil
should be removed with a vacuum cleaner. If a vacuum
cleaner is not available, a soft brush may be used. The cleaning tool should be applied in the direction of the fins. Coil
surfaces can be easily damaged (fin edges bent over) if the
tool is applied across the fins.
NOTE: Use of a water stream, such as a garden hose, against
a surface loaded coil will drive the fibers and dirt into the
coil. This will make cleaning efforts more difficult. Surface
debris must be completely removed prior to using low velocity clean water rinse.
Periodic Clean Water Rinse
A periodic clean water rinse is very beneficial for coils that
are applied in coastal or industrial environments. However,
it is very important that the water rinse is made with very
low velocity water stream to avoid damaging the fin edges.
Monthly cleaning is recommended.

—23—

The following field supplied equipment is required for coil
cleaning:
• 21/2 gallon garden sprayer
• water rinse with low velocity spray nozzle
Environmentally Sound Coil Cleaner Application Instructions
Perform the following procedure to clean the coil.
NOTE: Wear proper eye protection such as safety glasses
during mixing and application.
1. Remove all surface debris and dirt from the coil with
a vacuum cleaner.
2. Thoroughly wet finned surfaces with clean water and
a low velocity garden hose, being careful not to bend
fins.
3. Mix Environmentally Sound Coil Cleaner in a
21/2 gallon garden sprayer according to the instructions included with the cleaner. The optimum
solution temperature is 100 F.
CAUTION: DO NOT USE water in excess of 130 F.
Enzymes in coil cleaner will be destroyed and coil
cleaner will not be effective.

Fig. 24 — Pivot and Support Top Cover

4. Thoroughly apply Environmentally Sound Coil
Cleaner solution to all coil surfaces including finned
area, tube sheets, and coil headers. Hold garden
sprayer nozzle close to finned areas and apply cleaner
with a vertical, up-and-down motion. Avoid spraying
in horizontal pattern to minimize potential for fin
damage. Ensure cleaner thoroughly penetrates deep
into finned areas. Interior and exterior finned areas
must be thoroughly cleaned.
5. Allow finned surfaces to remain wet with cleaning
solution for 10 minutes. Ensure surfaces are not
allowed to dry before rinsing. Reapply cleaner as
needed to ensure 10-minute saturation is achieved.
6. Thoroughly rinse all surfaces with low velocity clean
water using downward rinsing motion of water spray
nozzle. Protect fins from damage from the spray
nozzle.

Fig. 25 — Coil Cleaning (Typical)

CAUTION: Do not use bleach, harsh chemicals, or
acid cleaners on outdoor or indoor coils of any kind.
These types of cleaners are difficult to rinse, and they
promote rapid corrosion of the fin collar — copper tube
connection. Only use the Environmentally Sound Coil
Cleaner.
Never use high pressure air or liquids to clean coils.
High pressures damage coils and increase the airside
pressure drop. To promote unit integrity, follow cleaning and maintenance procedures in this document.

Routine Cleaning of E-Coated Coil Surfaces
Monthly cleaning with Environmentally Sound Coil Cleaner
is essential to extend the life of coils. It is recommended
that all coils including standard aluminum, pre-coated,
copper/copper, or E-coated coils be cleaned with the Environmentally Sound Coil Cleaner as described below. Coil cleaning should be part of the regularly scheduled maintenance
procedures of the unit to ensure long life of the coil. Failure
to clean the coils may result in reduced durability in the
environment.
Environmentally Sound Coil Cleaner is non-bacterial,
biodegradable and will not harm the coil or surrounding
components such as electrical wiring, painted metal surfaces
or insulation. Use of non-recommended coil cleaners is
strongly discouraged since coil and unit durability could be
affected.

X. REPLACEMENT PARTS
A complete list of replacement parts is available from your
Bryant dealer.

—24—

—25—

TROUBLESHOOTING CHART — HEATING CYCLE

LEGEND
CCH — Crankcase Heater
N.C. — Normally Closed

Printed in U.S.A.

CATALOG NO. 5357-506

TROUBLESHOOTING CHART — COOLING CYCLE

CCH —
TXV —

LEGEND
Crankcase Heater
Thermostatic Expansion Valve

START-UP CHECKLIST
I. PRELIMINARY INFORMATION
OUTDOOR UNIT: MODEL NO. _______________________________

SERIAL NO.: __________________________________

INDOOR UNIT: MODEL NO. _________________________________

SERIAL NO.: __________________________________

ADDITIONAL ACCESSORIES __________________________________________________________________________________
II. PRE-START-UP
OUTDOOR UNIT
IS THERE ANY SHIPPING DAMAGE? (Y/N)____________
IF SO, WHERE: ________________________________________________________________________________________________
_______________________________________________________________________________________________________________
WILL THIS DAMAGE PREVENT UNIT START-UP? (Y/N) _____________
CHECK POWER SUPPLY. DOES IT AGREE WITH UNIT? (Y/N) _____________
HAS THE GROUND WIRE BEEN CONNECTED? (Y/N) ____________
HAS THE CIRCUIT PROTECTION BEEN SIZED AND INSTALLED PROPERLY? (Y/N) ___________
ARE THE POWER WIRES TO THE UNIT SIZED AND INSTALLED PROPERLY? (Y/N) ___________
HAVE COMPRESSOR HOLDDOWN BOLTS BEEN LOOSENED (Washers are snug, but not tight)?
(Y/N) _______________
CONTROLS
ARE THERMOSTAT AND INDOOR FAN CONTROL WIRING
CONNECTIONS MADE AND CHECKED? (Y/N) _______________
ARE ALL WIRING TERMINALS (including main power supply) TIGHT? (Y/N) ______________
HAS CRANKCASE HEATER BEEN ENERGIZED FOR 24 HOURS?

(Y/N) ______________

INDOOR UNIT
HAS WATER BEEN PLACED IN DRAIN PAN TO CONFIRM PROPER DRAINAGE?

(Y/N) ____________

ARE PROPER AIR FILTERS IN PLACE? (Y/N) ______________
HAVE FAN AND MOTOR PULLEYS BEEN CHECKED FOR PROPER ALIGNMENT?

(Y/N) ____________

DO THE FAN BELTS HAVE PROPER TENSION? (Y/N) ________________
HAS CORRECT FAN ROTATION BEEN CONFIRMED? (Y/N)________________
PIPING
HAVE LEAK CHECKS BEEN MADE AT COMPRESSOR, OUTDOOR UNIT, INDOOR UNIT,
TXVs (Thermostatic Expansion Valves), SOLENOID VALVES, FILTER DRIERS, AND FUSIBLE
PLUGS WITH A LEAK DETECTOR? (Y/N) ________________
LOCATE, REPAIR, AND REPORT ANY LEAKS. _________________________________________________________________
HAVE ALL COMPRESSOR SERVICE VALVES BEEN FULLY OPENED (BACKSEATED)? (Y/N)___________
HAS LIQUID LINE SERVICE VALVE BEEN OPENED? (Y/N)___________
IS THE OIL LEVEL IN COMPRESSOR CRANKCASE VISIBLE IN THE COMPRESSOR SIGHT GLASS?
(Y/N) _______________
CHECK VOLTAGE IMBALANCE
LINE-TO-LINE VOLTS:

AB ___________ V

AC___________ V

BC ___________V

(AB + AC + BC)/3 = AVERAGE VOLTAGE = ________________V
MAXIMUM DEVIATION FROM AVERAGE VOLTAGE =_______________V
VOLTAGE IMBALANCE = 100 X (MAX DEVIATION)/(AVERAGE VOLTAGE) = _______________ %
IF OVER 2% VOLTAGE IMBALANCE, DO NOT ATTEMPT TO START SYSTEM!
CALL LOCAL POWER COMPANY FOR ASSISTANCE.

CL-1

III. START-UP

OIL PRESSURE
SUCTION PRESSURE
SUCTION LINE TEMP
DISCHARGE PRESSURE
DISCHARGE LINE TEMP
ENTERING OUTDOOR AIR
LEAVING OUTDOOR AIR TEMP
INDOOR ENTERING-AIR DB (dry bulb) TEMP
INDOOR ENTERING-AIR WB (wet bulb) TEMP
INDOOR LEAVING-AIR DB TEMP
INDOOR LEAVING-AIR WB TEMP
COMPRESSOR AMPS (L1/L2/L3)

COOLING
__________________
__________________
__________________
__________________
__________________
__________________
__________________
__________________
__________________
__________________
__________________

_______ / _______ / _______

HEATING
__________________
__________________
__________________
__________________
__________________
__________________
__________________
__________________
__________________
__________________
__________________
_______ / _______ / _______

CHECK THE COMPRESSOR OIL LEVEL SIGHT GLASSES; ARE THE SIGHT GLASSES SHOWING
OIL LEVEL IN VIEW? (Y/N)

CUT ALONG DOTTED LINE

CHECK INDOOR FAN SPEED AND RECORD. _______________
CHECK OUTDOOR FAN SPEED AND RECORD. ________________
AFTER AT LEAST 10 MINUTES RUNNING TIME, RECORD THE FOLLOWING MEASUREMENTS:

NOTES:
______________________________________________________________________________________________________________
______________________________________________________________________________________________________________
______________________________________________________________________________________________________________
______________________________________________________________________________________________________________
______________________________________________________________________________________________________________
______________________________________________________________________________________________________________
______________________________________________________________________________________________________________
______________________________________________________________________________________________________________
______________________________________________________________________________________________________________
______________________________________________________________________________________________________________
______________________________________________________________________________________________________________

CUT ALONG DOTTED LINE

______________________________________________________________________________________________________________

Printed in U.S.A.

10-05A

CL-2

CATALOG NO. 5357-506

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Bryant 541A Users Manual

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