LENNOX Air Conditioner/heat Pump(outside Unit) Manual L0806498

User Manual: LENNOX LENNOX Air conditioner/heat pump(outside unit) Manual LENNOX Air conditioner/heat pump(outside unit) Owner's Manual, LENNOX Air conditioner/heat pump(outside unit) installation guides

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LENNOX
,1,_2003 Lennox industries inc.
Dallas, Texas

INSTALLATION
INSTRUCTIONS
HPXB15 SERIES UNITS
HEAT PUMP UNITS
504,735M
12/03
Supersedes 07/03

HPXB15 outdoor units use R410A which is an ozone
friendly HFC refrigerant. This unit must be installed with a
matching indoor coil and line set as outlined in the Lennox
Engineering Handbook. HPXB15 outdoor units are designed for use in expansion valve (TXV) systems only.
They are not designed to be used with other refrigerant flow
control devices. The Lennox Engineering Handbook lists
indoor TXV kits that must be ordered separately.

A, IMPORTANT

_
Technical
_z-_j_LL[
i i i Publications
Lithe U.S.A.

HPXB15 Outdoor Unit ...........................
Shipping & Packing List .........................
General Information .............................
Dimensions ....................................
Parts Arrangement
.............................
Setting the Unit .................................
Electrical ......................................
Refrigerant Piping ..............................
Refrigerant Metering Device .....................
Flushing Existing Line Set & Indoor Coil ...........
Manifold Gauge Set .............................
Service Valves .................................
Leak Testing ...................................
Evacuation ...................................
Start-Up ......................................
Charging
....................................
System Operation .............................
Defrost System ...............................
Maintenance ..................................
Optional Accessories ...........................
Homeowner Information ........................
HPXB15 Check Points .........................

1
1
1
2
3
3
4
6
6
7
8
8
9
10
11
11
15
16
18
19
19
20

RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE

1 - Assembled HPXB15 outdoor unit

,A WARNING

2 - Grommets (for liquid and vapor lines)
Check equipment for shipping damage. If you find any
damage, immediately contact the last carrier.

These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
who have jurisdiction before installation.

,&,WARNING

12/03

IIIIIIIIIIIIIIIIIIIIIIII1,1111111111111
Page 1

504,735M

IIil!111111,111,111,1

inlet

air

inlet

0
air
compressor

coil drain outlets
(around perimeter
of base)

air
Top View
electrical
inlets

discharge

air

vapor
line inlet

4-1/2 (114)

liquid
line inlet
2 -3/4
(70)

2
(51)

1-3/8
(35)

Side View
Model No.

JR.

27-7/8

25-7/8

29-7/8

12-1/4

708

657

759

30-7/8

32-1/8

34-1/16

HPXB15-024

HPXB15-030

in.

HPXB15-036

mm
in.

22-7/16

14-7/16

22-1/8

16-3/4

2-7/8

5-1/2

311

570

367

562

425

730

140

12-3/4

26-5/8

18-5/8

28-1/8

17-1/4

3-7/8

7-1/2

784

816

865

324

676

473

718

438

191

34-7/8

32-1/8

34-1/16

13-3/4

26-5/8

18-5/8

28-1/8

18-1/4

3-7/8

7-1/2

886

816

865

349

676

473

718

464

191

44-7/8

32-1/8

34-1/16

14-1/4

26-5/8

18-5/8

28-1/8

18-3/4

3-7/8

7-1/2

1140

816

865

362

676

473

718

476

191

HPXB15-042
mm
HPXB15-048

in.

HPXB15-060

Page 2

system operation

defrost control/timed-off control
contactor

monitor \

ground lug

high pressure

sensing bulb

switch
vaporline
service valve
and gauge port

filter/drier

liquid line
service valve
and gauge port

expansion valve
with internal

defrost
thermostat
crankcase heater
thermostat
distributor
reversing valve
and solenoid
compressor
terminal plug

crankcase
heater

muffler

Figure

1
3 - In heavy snow areas, do not locate unit where drifting
will occur. The unit base should be elevated above the
depth of average snows.

ACAUTION

NOTE - Elevation of the unit may be accomplished by
constructing a frame using suitable materials. If a support frame is constructed, it must not block drain holes
in unit base.

XkCAUTION

Installation

These units operate under a wide range of weather conditions; therefore, several factors must be considered when
positioning the outdoor unit. The unit must be positioned to
give adequate clearances for sufficient airflow and servicing. A minimum clearance of 24 inches (610 mm) between
multiple units must be maintained. Refer to figure 2 for installation clearances.
1 - Place a sound-absorbing material, such as Isomode,
under the unit if it will be installed in a location or position that will transmit sound or vibration to the living
area or adjacent buildings.

NOTE - A service access
clearance of 30" (762 mm)
must be maintained in front
of the service access panel.
Clearance to one side must
be 36" (914 mm). Clearance
to one of the remaining two
sides may be 12" (304 mm)
and the final side may be 6"
(152 mm).

Clearances

as noted

I as noted

30"
(762ram)

NOTE - A clearance of 24" (610 mm)
must be maintained between two unit&

NOTE - 48" (1219 mm) clearance required on top
of unit. Maximum soffit overhang is 36" (914 mm).

2 - Mount unit high enough above ground or roof to allow
adequate drainage of defrost water and prevent ice
build-up.

Page 3

Figure 2
4 - When installed in areas where low ambient temperatures exist, locate unit so winter prevailing winds do
not blow directly into outdoor coil.

5 - Locateunitawayfromoverhanging
rooflineswhich
wouldallowwateror icetodropon,orinfrontof,coilor
intounit,

Rooftop Application
Wind Barrier Construction
prevailing winter winds

Slab Mounting

wind barrier

When installing unit at grade level, top of slab should be
high enough above the grade so that water from higher
ground will not collect around unit, See figure 3. Slab
should have a slope tolerance away from the building of 2
degrees or 2 inches per 5 feet (51 mm per 1.5 m), This will
prevent ice build-up under unit during a defrost cycle. Refer
to roof mounting section for barrier construction if unit must
face prevailing winter winds.

2 degrees or
2 in. per 5 foot
(51 mm per 1.5 m)
slope tolerance away
from building structure

I
INLET

0
AIR

I
I

air

building
structure

IL
24"
(610 ram)

Slab Mounting
discharge

]

inlet air

0
inlet air

CL-

Figure 4

CLIn the U,S,A., wiring must conform with current local codes
and the current National Electric Code (NEC). In Canada,
wiring must conform with current local codes and the current
Canadian Electrical Code (CEC),

-T
mounting

C[-

slab

Refer to the furnace or blower coil installation instructions
ground level

Figure

for additional wiring application diagrams and refer to unit
nameplate for minimum circuit ampacity and maximum
overcurrent protection size.

Roof Mounting

WARNING

Install the unit a minimum of 6 inches (152 mm) above the
roof surface to avoid ice build-up around the unit. Locate
the unit above a load bearing wall or area of the roof that
can adequately support the unit, Consult local codes for
rooftop applications,
If unit coil cannot be mounted away from prevailing winter
winds, a wind barrier should be constructed. See figure 3,
Size barrier at least the same height and width as outdoor
unit, Mount barrier 24 inches (610 mm) from the sides of the
unit in the direction of prevailing winds.

Page 4

1 -Install line voltage power supply to unit from a properly
sized disconnect switch,
2 -Ground unit at unit disconnect switch or to an earth
ground.

side the unit control box cover.

NOTE - To facilitate conduit, a hole is in the bottom of
the control box. Connect conduit to the control box us

3 - Install room thermostat (ordered separately) on an inside wall approximately in the center of the conditioned
area and 5 feet (1.5 m) from the floor. It should not be
installed on an outside wall or where it can be affected

ing a proper conduit fitting.
NO TE - Units are approved for use only with copper
conductors.
24V, Class II circuit connections are made in the low
voltage junction box. Refer to figure 5 for field wiring
diagram.

by sunlight, drafts or vibrations.
4 - Install voltage wiring from outdoor to indoor unit and
from thermostat to indoor unit. See figures 6 and 7.

NOTE - A complete unit widn_l dia_lram is located in

Typical
B4
OUTDOOR FAN
(LEADED)

Field Wiring

SYSTEM
OPERATION
MONITOR

ORANGE-RUN
=COMMON

Diagram

GROUND
E

_---

Ik,

AN
Y,OUT

DEFROST
CONTROL

PURPLE=
CAPACITOR

HI -PS

LUG,S_

KI
COMPRESSOR
DONTACTOR

z_
L2

L0-PS

CI2
DUAL

208-230/60/1
main power

wo
O0

CAPACITOR
OUT
_0

z_NOTEFOR USE WITH COPPER
CONDUCTORS
ONLY.REFER
TO UNIT RATING
PLATE FOR MINIMUM
CIRCUIT
AMPACITY
AND MAXIMUM
OVERCURRENT
PROTECTION
SIZE
/_

Figure 5

Page 5

WARNINGELECTRIC
SHOCK HAZARD,CAN
CAUSE
INJURY
OR DEATH.UNIT
MUST BE GROUNDED
IN
ACCORDANCE
WITH NATIONAL
AND LOCAL CODES.

Field refrigerant piping consists of liquid and vapor lines
from the outdoor unit (sweat connections) to the indoor coil
(flare or sweat connections). Use Lennox L15 (sweat, nonflare) series line sets as shown in table 1 or use field-fabricated refrigerant lines, Valve sizes are listed in table 1.

Outdoor Unit and Blower Unit
Thermostat Designations
(Some connections

may not apply.

Refer to specific thermostat

Thermostat

and indoor unit.)

Indoor
Unit

Outdoor
Unit

Refrigerant Connections
HPXB15 Matched with New Indoor Coil and Line Set

®
@

If an existing indoor coil which was equipped with an
RFCI metering device is being replaced, the liquid line
must also be replaced prior to the installation of the
HPXB15 unit.

power
power

common
common

_(__

1st. stage aux. heat

1st.

s_e

aux. hea_l

Table 1

Refrigerant

Line Sets

Valve Field Size
Recommended
indoor

blower

reversing

compressor

Line Set

Connections

-(b

Model

valve

L15
Line Sets

Liquid
Line

Vapor
Line

Liquid
Line

Vapor
Line

-024
-030
-036

3/8 in,
10mm

3/4 in,
19mm

3/8 in,
10mm

3/4 in,
19mm

L15-41
15 ft. - 50 ft.
4.6 m- 15 m

-042
-048

3/8 in.
10mm

7/8 in.
22mm

3/8 in.
10mm

7/8 in.
22mm

L15-65
15 ft. - 50 ft.
4.6m15m

-060

3/8 in,
10 mm

1-1/8 in,
29 mm

3/8 in.
10 mm

1-1/8 in,
29 mm

Field
Fabricated

Figure 6

Outdoor Unit and Blower Unit
Thermostat Designations
(with auxiliary heat)
(Some connections

NOTE - Units are designed for line sets of up to 50 feet (15
m). Select line set diameters from table 1 to ensure that oil
returns to the compressor.
Installing Refrigerant Line

may not apply.

Refer to specific thermostat and indoor unit.)

Thermostat

Outdoor
Unit

Indoor
Unit
power

common

__.

emergency

During the installation of any heat pump or a/c system, it is
important to properly isolate the refrigerant lines to prevent
unnecessary vibration, Line set contact with the structure
(wall, ceiling or floor) causes some objectionable noise
when vibration is translated into sound, As a result, more
energy or vibration can be expected, Closer attention to
line set isolation must be observed,

®1

power

heat I -

he
_"cOmmat
em'_
_

I
I
/

eutdger t'stat

1st. stage aux. TTeaq-_-st._stTg _.

®
®

indoor btower

compressor

®1

_at

Following are some points to consider when placing and
installing a high-efficiency outdoor unit:

@1
®1

1-Placement
- Be aware some localities are adopting
sound ordinances based on how noisy the unit is from

®[
®1

reversinq.vatve

Figure

the adjacent property not at the original installation.
Install the unit as far as possible from the property line,
When possible, do not install the unit directly outside a
window, Glass has a very high level of sound transmission.

If the HPXB15 unit is being installed with a new indoor coil
and line set, the refrigerant connections should be made as
outlined in this section. If an existing line set and/or indoor
coil is going to be used to complete the HPXB15 system,
refer to the following section which includes flushing procedures.

2- Line Set Isolation - The following illustrations demonstrate procedures which ensure proper refrigerant line
set isolation. Figure 8 shows how to install line sets on
vertical runs. Figure 9 shows how to install line sets on
horizontal runs, Figure 10 shows how to make a transition from horizontal to vertical, Finally, figure 11 shows
how to place the outdoor unit and line set,

Page 6

Refrigerant Line Sets
How To Install Vertical Runs
(new construction shown)
NOTE - Similar installation practices should be used if
line set is to be installed on exterior of outside waft.
Outside Wall

IMPORTANT- Refrigerant
lines must not contact wall.

Vapor Line

Liquid Line

Wood Block
Between Studs

Wire Tie
\

Inside Wall

Strap
_

-Vapor LiLn_uid Lin-'_

Sleeve
Wire Tie

(wrapped with

--_-------

Outside Wall

"_ _--------

Wood Block
Wire Tie
Strap

g__Caulk
PVC Pipe

_" _

Fiberglass
Insulation

IMPORTANT- Refrigerant
lines must not contact
structure,

Figure 8

Page 7

Sleeve

Refrigerant Line Sets:
Installing Horizontal Runs

To hang line set from joist or rafter,
use either metal strapping material
or anchored heavy nylon wire ties.

Wire Tie
(around vapor line only)

8 feet

I
I

Floor Joist or
Roof Rafter
/

Tape or Wire Tie

8 feet

Strapping Material (around vapor line only)

Metal Sleeve
\

Tape or Wire Tie

,
r

Floor Joist or Roof Rafterf_

Strap the vapor line to the joist or rafter at 8 ft.
intervals then strap the liquid line to the vapor line.

Figure 9

Page 8

Refrigerant Line Sets:
Transition From Vertical To Horizontal
Automotive
Muffler-Type
Hanger

AnchoredHeavy
NylonWireTie

Wall
Stud

Wall
Stud
Strap Liquid Line
To Vapor Line

Strap Liquid Line
To Vapor Line
Liquid Line

Sleeve

Vapor Line
Wrapped in
Armaflex

Metal
Sleeve

Liquid Line
Figure

Vapor Line
Wrapped in
Armaflex

Outside Unit Placement and Installation

Install unit away from windows.

Two 90 ° elbows
installed in line set
will reduce line set
vibration.

Figure

Page 9

IsolationGrommets
Locatetheprovided
isolationgrommets.
Usea knifetoslit
thewebbingoneachgrommet.
Slidelargergrommetonto
vaporlineand smallergrommetontoliquidline.Insert
grommetsinto mullionto isolaterefrigerantlines from
sheetmetaledges.

Metering Device Installation

distributor

o-ring

expanston

&WARNING

valve

o-ring
liquid li_
stub

Figure
12

Brazing Connection Procedure
1 - The end of the refrigerant line must be cut square and
its internal shape must remain round. The line must be
free of nicks or dents and must be deburred (I.D. and
O.D.)

& IMPORTANT

2 - Before making line set connections, use dry nitrogen to
purge the refrigerant piping. This will help to prevent
oxidation and the introduction of moisture into the system.
3 - Use silver alloy brazing rods (5 or 6 percent minimum
silver alloy for copper-to-copper brazing or 45 percent

&WARNING

silver alloy for copper4o-brass or copper4o-steel brazing). Wrap a wet cloth around the valve body and the
copper tube stub. Remove light maroon washers from
service valves and shield light maroon stickers in order
to protect them during brazing. Braze the line set to the
service valve.
4 - Quench the joint with water or a wet cloth to prevent
heat damage to the valve core and opening port.
IMPORTANT - The tube end must stay bottomed in the
fitting during final assembly to ensure proper seating,
sealing and rigidity.

HPXB15 units are used in check expansion valve systems
only. Check expansion valves equipped with Chatleff fittings are available from Lennox. Refer to the Engineering
Handbook for applicable expansion valves for use with
specific match-ups.
If you install a check expansion valve with an indoor coil
that includes a fixed orifice, remove the orifice before
installing the check expansion valve.
See figure 12 for installation of the check expansion valve.

Page 10

&IMPORTANT

that the entire system is completely void of refrigerant.
Disconnect the liquid and vapor lines from the existing
outdoor unit,

ACAUTION

ff the existing outdoor unit is equipped with manual shut-off valves AND you plan to use NEW R22
refrigerant to flush the system -- Start the existing
R22 system in the cooling mode and close the liquid
line valve, Pump all of the existing R22 refrigerant
back into the outdoor unit, (It may be necessary to bypass the low pressure switches to ensure complete refrigerant evacuation,) When the low side system pres-

IMPORTANT

sures reach 0 psig, close the vapor line valve.
Disconnect all power to the existing outdoor unit, Refer to gauges after shutdown to confirm that the valves
Required

You will need the following equipment in order to flush the
existing line set and indoor coil: two clean R22 recovery
bottles, an oilless recovery machine with a pump down feature, and two sets of gauges (one for use with R22 and one
for use with the R410A).
Flushing

are not allowing refrigerant to flow back into the low
side of the system, Disconnect the liquid and vapor
lines from the existing outdoor unit,

Equipment

connections. DO NOT install the field-provided
R410A check/expansion
valve at this time.
Make low voltage and line voltage connections to the
new outdoor unit. DO NOT turn on power to the unit
or open the outdoor unit service valves at this
time.

Procedure

1 - Remove existing R22 refrigerant using the appropriate procedure below.
If the existing outdoor unit is not equipped with
shut-off valves, or if the unit is not operational
AND you plan to use the existing R22 refrigerant to
flush the system -- Disconnect all power to the existing outdoor unit. Connect the existing unit, a clean recovery cylinder and the recovery machine according
to the instructions provided with the recovery machine, Remove all R22 refrigerant from the existing
system. Refer to gauges after shutdown to confirm

Page 11

Remove the existing outdoor unit, Set the new R410A
unit and follow the brazing connection procedure
which begins on the previous page to make line set

Remove the existing refrigerant flow control orifice or
thermal expansion/check valve before continuing with
flushing procedures. The existing devices are not approved for use with R410A refrigerant and may prevent proper flushing, Use a field-provided fitting to reconnect the lines.

Flushing

Connections

Inverted R22 Cylinder
(Contains clean R22 to
be used for flushing)

LOW
PRESSURE

HIGH
PRESSURE

HPXB15 Unit
EXISTING

Existinc

VAPOR LINE
Op{_C:[ENI
E:AU

EXISTING

GE MAN::_:

_:_

LIQUID LINE

Indoor Coil

NOTE - The inverted R22 cylinder must contain at least the same amount of refrigerant
as was recovered from the existing system.

TANK
INLET RETURN
DISCHARGE
RECOVERY
CYLINDER

Recovery Machine
Figure

A, IMPORTANT

13
7- After all of the liquid refrigerant has been recovered,
switch the recovery machine to vapor recovery so that
all of the R22 vapor is recovered,
NOTE- A single system flush should remove all of the
mineral oil from the existing refrigerant lines and in-

Remove the pressure tap valve cores from the
H PXB 15 unit's service valves, Connect an R22 cylinder with clean refrigerant to the vapor service valve.
Connect the R22 gauge set to the liquid line valve and
connect a recovery machine with an empty recovery
tank to the gauge set,

5 - Set the recovery machine for liquid recovery and start
the recovery machine, Open the gauge set valves to
allow the recovery machine to pull a vacuum on the existing system line set and indoor coil,
6 - Invert the cylinder of clean R22 and open its valve to
allow liquid refrigerant to flow into the system through
the vapor line valve, Allow the refrigerant to pass from
the cylinder and through the line set and the indoor coil
before it enters the recovery machine,

door coil. A second flushing may be done (using clean
refrigerant) if insufficient amounts of mineral oil were
removed during the first flush. Each time the system
is flushed, you must allow the recovery machine
to pull a vacuum
procedure.

on the system

at the end of the

8- Close the valve on the inverted R22 drum and the
gauge set valves, Pump the remaining refrigerant out
of the recovery machine and turn the machine off,
9 - Use nitrogen to break the vacuum on the refrigerant
lines and indoor coil before removing the recovery machine, gauges and R22 refrigerant drum, Reinstall
pressure tap valve cores into HPXB15 service valves,
10 -Install the provided check/expansion valve (approved
for use with R410A refrigerant) in the liquid line at the
indoor coil,

Page 12

NO TE - Use a 3/16" h ex head extension for liquid line
sizes or a 5/16" extension for vapor line sizes.
3 - Replace stem cap and tighten it firmly. Tighten finger
tight, then tighten an additional 1/6 turn.
To Close Service Valve:

A IMPORTANT

1 - Remove stem cap with an adjustable wrench,
2 - Using service wrench and hex head extension, turn
stem clockwise to seat valve, Tighten it firmly,
NOTE - Use a 3/16" hex head extension for liquid line
sizes or a 5/16" extension for vapor line sizes.
3 - Replace stem cap. Tighten finger tight, then tighten an
additional 1/6 turn.
Vapor

Access the liquid line and vapor line service valves (figures
14 and 15) and gauge ports are used for leak testing, evacuating, charging and checking charge, See table 2 for
torque requirements,
Each valve is equipped with a service port which has a factory-installed Schrader valve. A service port cap protects
the Schrader valve from contamination and serves as the

Liquid Service
Table 2

Part

Type) Valve

Vapor line service valves function the same way as the other valves, the difference is in the construction, These
valves are not rebuildable. If a valve has failed, you must
replace it. A ball valve valve is illustrated in figure 15,
The ball valve is equipped with a service port with a factoryinstalled Schrader valve. A service port cap protects the
Schrader valve from contamination and assures a leakfree seal,

primary leak seal,
Torque

Line (Ball

Valve (Valve

Insert Hex
Wrench

Open)
Stem Cap

Requirements
Recommended

Torque

Service valve cap

8 ft.- lb.

11 NM

Sheet metal screws

16 in.- lb.

2 NM

Machine screws #10

28 in.-lb.

3 NM

Compressor bolts

90 in.- lb.

10 NM

Gauge port seal cap

8 ft.- lb.

11 NM

Field Side

Schrader
Valve
Unit Side
Service Port
Cap
Service

IMPORTANT

Liquid

Port

Service

Valve (Valve

Field Side

_..----._

Closed)
Stem Cap

Insert Hex
Wrench Here

To Access

Schrader

Port:

Service
Port

1 - Remove service port cap with an adjustable wrench,
2 - Connect gauge to the service port.
3 - When testing is complete, replace service port cap,
Tighten finger tight, then an additional 1/6 turn,
To Open Service Valve:
1 - Remove stem cap with an adjustable wrench.
2 - Using service wrench and hex head extension, back
the stem out counterclockwise as far as it will go,

(Valve Front
Seated)

Service Port
Cap

Unit Side

Schrader Valve Open
To Line Set When Valve Is

Page 13

Closed (Front Seated)
Figure

3 - Open the high pressure side of the manifold to allow
the R410A into the line set and indoor unit. Weigh in a
trace amount of R410A. [A trace amount is a maximum
of 2 ounces (57 g) or 3 pounds (31 kPa) pressure.]
Close the valve on the R410A cylinder and the valve
on the high pressure side of the manifold gauge set.
Disconnect the R410A cylinder.

Vapor Line (Ball Type) Service Valve
(Valve Open)
Use Adjustable Wrench
To open: rotate stem counter-clockwise
90 ° .
To close: rotate stem clockwise 90 °.

cap port
service

unit side

4 - Connect a cylinder of nitrogen with a pressure regulating valve to the center port of the manifold gauge set.

S charlavde
r_

5 - Connect the manifold gauge set high pressure hose to
the vapor valve service port. (Normally, the high pressure hose is connected to the liquid line port; however,
connecting it to the vapor port better protects the manifold gauge set from high pressure damage.)

service
port

ste m

6 - Adjust the nitrogen pressure to 150 psig (1034 kPa).
Open the valve on the high side of the manifold gauge
set which will pressurize line set and indoor unit.

field side
ball
(shown open)

Figure

stem cap

After the line set has been connected to the indoor and outdoor units, the line set connections and indoor unit must be
checked for leaks.

7 - After a few minutes, open a refrigerant port to ensure
the refrigerant you added is adequate to be detected.
(Amounts of refrigerant will vary with line lengths.)
Check all joints for leaks. Purge nitrogen and R410A
mixture. Correct any leaks and recheck.

,IMPORTANT

WARNING

Evacuating the system of noncondensables is critical for
proper operation of the unit. Noncondensables are defined
as any gas that will not condense under temperatures and
pressures present during operation of an air conditioning
system. Noncondensables and water vapor combine with
refrigerant to produce substances that corrode copper piping and compressor parts.

AWARNING

A IMPORTANT
WARNING
1 - Connect the manifold gauge set to the service valve
ports as follows:
• low pressure gauge to vapor line service valve
• high pressure gauge to liquid line service valve

Using an Electronic

Close manifold gauge set valves. Connect the center
manifold hose to an upright cylinder of R410A.

Leak Detector

1 - Connect a cylinder of R410A to the center port of the
manifold gauge set.
2 - With both manifold valves closed, open the valve on
the R410A cylinder (vapor only).

2 - Connect micron gauge,
3 - Connect the vacuum pump (with vacuum gauge) to the
center port of the manifold gauge set.
4 - Open both manifold valves and start vacuum pump,

Page 14

5 - Evacuate
the linesetandindoorunitto anabsolute
pressureof23,000microns(29.01inchesof mercury).Duringtheearlystagesof evacuation,
it is desirabletoclosethemanifold
gaugevalveatleastonceto
determine
ifthereisa rapidriseinabsolute pressure.

IMPORTANT

A rapid rise in pressure indicates a relatively large leak.
If this occurs, repeat the leak testing procedure.
NOTE - The term absolute pressure means the total
actual pressure within a given volume or system,
above the absolute zero of pressure. Absolute pressure in a vacuum is equal to atmospheric pressure minus vacuum pressure.
6 - When the absolute pressure reaches 23,000 microns
(29.01 inches of mercury), close the manifold gauge
valves, turn off the vacuum pump and disconnect the
manifold gauge center port hose from vacuum pump.
Attach the manifold center port hose to a nitrogen cylinder with pressure regulator set to 150 psig (1034 kPa)
and purge the hose. Open the manifold gauge valves
to break the vacuum in the line set and indoor unit.
Close the manifold gauge valves.

1 - Rotate fan to check for frozen bearings or binding.
2 - Inspect all factory- and field-installed
connections.

wiring for loose

3 - After evacuation is complete, open the liquid line and
vapor line service valves (counterclockwise) to release
refrigerant charge (contained in outdoor unit) into the
system.
4 - Replace stem caps and secure finger tight, then tighten an additional (1/6) one-sixth of a turn.
5- Check voltage supply at the disconnect switch. The
voltage must be within the range listed on the unit
nameplate. If not, do not start the equipment until the
power company has been consulted and the voltage
condition has been corrected.
6 - Set the thermostat for a cooling demand, turn on power
to indoor blower unit and close the outdoor unit disconnect to start the unit.

XkWARNING

7 - Recheck voltage while the unit is running. Power must
be within range shown on the nameplate.

7 - Shut off the nitrogen cylinder and remove the manifold
gauge hose from the cylinder. Open the manifold
gauge valves to release the nitrogen from the line set
and indoor unit.
8 - Reconnect the manifold gauge to the vacuum pump,
turn the pump on, and continue to evacuate the line set
and indoor unit until the absolute pressure does not
rise above 500 microns (29.9 inches of mercury) within
a 20-minute period after shutting off the vacuum pump
and closing the manifold gauge valves.
9 - When the absolute pressure requirement above has
been met, disconnect the manifold hose from the vacuum pump and connect it to an upright cylinder of R410A
refrigerant. Open the manifold gauge valves to break
the vacuum from 1 to 2 psig positive pressure in the line
set and indoor unit. Close manifold gauge valves and
shut off the R410A cylinder and remove the manifold
gauge set,

This system is charged with R410A refrigerant which operates at much higher pressures than R22. The check/expansion valve provided with the unit is approved for use
with R410A. Do not replace it with a valve designed for use
with R22. This unit is NOT approved for use with coils which
include metering orifices or capillary tubes.
Processing Procedure
The unit is factory-charged with the amount of R410A refrigerant indicated on the unit rating plate. This charge is
based on a matching indoor coil and outdoor coil with a 15
foot (4.6 m) line set. For varying lengths of line set, refer to
table 3 for refrigerant charge adjustment.
Table 3
Liquid Line Set
Diameter
3/8 in.
(10 ram)

Oz. per 5 ft. (grams per 1.5 m) adjust
from 15 ft. (4.6 m) line set*
3 ounces per 5 feet
(85g per 1.5 m)

*If line length is ,reater than 15 ft. (4.6 m), add this amount.
If line length is less than 15 ft. (4.6 m), subtract this amount.

Page 15

klMPORTANT

The compressor is charged with sufficient polyol ester
oil for line set lengths up to 50 ft.
The outdoor unit should be charged during warm weather.
However, applications arise in which charging must occur
in the colder months. The method of charging is determined by the unit's refrigerant metering device and the outdoor ambient temperature.

O,ock,n00u,0oor
Coi,

|
|
|
|
r

*Outdoor coil should be
blocked one side
at a time with cardboard
or plastic sheet until proper
testing pressures
are reached.
cardboard or
plastic sheet

Measure the liquid line temperature and the outdoor ambient temperature as outlined below:
1- Connect manifold gauge set to service valves as
shown in figure 17:
• low pressure gauge to vapor valve service port
• high pressure gauge to liquid valve service port
Connect the center manifold hose to an upright cylinder of R410A, Close manifold gauge set valves.
2 - Set the room thermostat to call for heat. This will create
the necessary load for properly charging the system in
the cooling cycle.

Figure

thermometer to record the liquid line temperature,
5 - The outdoor temperature will determine which charging method to use, Proceed with the appropriate charging procedure.
Weighing

in the Charge

Outdoor

TXV Systems

Temp. < 65°F

1 - With the manifold gauge hose still on the liquid service
port and the unit operating stably, use a digital thermometer to record the liquid line temperature.
2 - At the same time, record the liquid line pressure reading.
3 - Use a temperature/pressure chart for R410A to determine the saturation temperature for the liquid line pressure reading. See table 7.
4 - Subtract the liquid line temperature from the saturation

3 - Use a digital thermometer to record the outdoor ambient temperature,
4 - When the heating demand has been satisfied, switch
the thermostat to cooling mode with a set point of 68_F
(20<%). When pressures have stabilized, use a digital

*4-sided
unit shown

temperature (according to the chart) to determine subcooling. (Saturation temperature - Liquid line temperature = Subcooling)
5 - Compare the subcooling value with those in table 4, If
subcooling is greater than shown, recover some refrigerant. If subcooling is less than shown, add some refrigerant, Be aware of the R410A refrigerant cylinder. It
will be light maroon-colored, Refrigerant should be
added through the vapor line valve in the liquid state.
Some R410A cylinders are equipped with a dip
tube that allows you to draw liquid refrigerant from

(18°C)

the bottom of the cylinder without turning the cylinder upside-down. The cylinder will be marked if it
is equipped with a dip tube.

If the system is void of refrigerant, or if the outdoor ambient
temperature is cool, the refrigerant charge should be
weighed into the unit. Do this after any leaks have been repaired.

Table 4
Subcooling

Values

for Charging

1 - Recover the refrigerant from the unit.
Model Number

2 - Conduct a leak check, then evacuate as previously
outlined.

Conversion

3 - Weigh in the unit nameplate charge.
If weighing facilities are not available or if you are charging
the unit during warm weather, follow one of the other procedures outlined below.
Subcooling
Outdoor

Method

HPXB15-024

5 + 1 (2.8 + .5)

HPXB15-030

8 + 1 (7.4 + .5)

HPXB15-036

5.5 + 1 (3 + .5)

HPXB15-042

4.5 + 1 (2.5 + .5)

HPXB15-048

2.5 + 1 (1.4 + .5)

HPXB15-060

6 + 1 (3.3 + .5)

Charging

Temp. < 65°F (18°C)

Subcooling
Values
Temp. - Liquid Line Temp. °F (°C)

Using

Normal

Operating

and the Approach

When the outdoor ambient temperature is below 65°F
(18°C), use the subcooling method to charge the unit, It
may be necessary to restrict the air flow through the outdoor coil to achieve pressures in the 325-375 psig
(2240-2585 kPa) range, These higher pressures are necessary for checking the charge. Block equal sections of air
intake panels and move obstructions sideways until the liquid pressure is in the 325-375 psig (2240-2585 kPa) range.
See figure 16,

Outdoor

Temp.

Pressures

Method

_>65°F (18°C)

The following procedure is intended as a general guide and
is for use on expansion valve systems only. For best results,
indoor temperature should be 70°F (21°C) to 80°F (26°C),
Monitor system pressures while charging.
1 - Record outdoor ambient temperature using a digital
thermometer.
2 - Attach high pressure gauge set and operate unit for
several minutes to allow system pressures to stabilize,

Page 16

3 - Comparestabilizedpressures
withthoseprovidedin
table6, <'Normal
OperatingPressures."Minorvariationsinthesepressures
maybeexpected
duetodifferencesin installations,
Significantdifferencescould
meanthatthesystemisnotproperlychargedorthata
problemexistswithsomecomponent
in the system.
Pressureshigherthanthoselistedindicatethatthe
systemis overcharged.
Pressureslowerthanthose
listedindicatethatthesystemis undercharged,
Verify
adjustedchargeusingtheapproachmethod.
ApproachMethod
4 - Usethesamedigitalthermometer
usedtocheckoutdoorambienttemperature
tocheckliquidlinetemperature.Verifytheunitchargeusingtheapproach
method,
5 - Thedifference
between
theambientandliquidtemperaturesshouldmatchvaluesgivenintable5.If thevaluesdon'tagreewiththethoseintable5,addrefrigerant to lowerthe approachtemperatureor recover
refrigerant
fromthesystemto increasetheapproach
temperature,

(Showing

Table 5
Approach
Model Number

Approach Temperature
Liquid Line Temp. - Outdoor Ambient °F (°C)

HPXB15-024

13 + 1 (7.2 + .5)

HPXB15-030

7 + 1 (3.9 + .5)

HPXB15-036

11 + 1 (6.1 + .5)

HPXB15-042

12.5 + 1 (6.9 + .5)

HPXB15-048

10 + 1 (5.6 + .5)

HPXB15-060

11.5 + 1 (6.5 + .5)

IMPORTANT

HPXB15 Cooling
Cycle
Gauge Manifold Connections)
OUTDOOR

DEFROST

UNIT

DISTRIBUTOR

THERM OSTAT-_._._

I
I
EXPANSION/

Values for Charging

NOTE - ARROWS
INDICATE
DIRECTION
OF REFRIGERANT
REVERSING

VALVE

FLOW

CHECK VALVE __
FILTER /
LOW
PRESSURE

OUTDOOR

1_ DR,ER CO,L

HIGH
PRESSURE

INDOOR

UNIT

VAPOR
SERVICE
/

°OAI

LINE
VALVE

DRU=
[[ sc y47St
--

POR__
--

--I--'_

VAPOR

COMPRESSO_

INDOOR
COIL

EXPANSION/CHECK
VALVE

NOTE-Use gauge ports on vapor line valve and liquid valve for evacuating refrigerant lines
and indoor coil. Use vapor gauge port to measure vapor pressure during charging.

Figure

Page 17

......

Table 6
Normal Operating Pressures
(Liquid +10 and Vapor +5 psig)
Outdoor Coil
Entering Air
Temp. °F (°C)
65 (18.3)
75 (23.9)
85 (29.4)
95 (35.0)
105 (40.6)
Outdoor Coil
Entering Air

HPXB15-024
Liquid
252
291
337
371
421

Cooling Operation
HPXB15-036

HPXB15-030

Vapor
131
133
135
140
142

HPXB15-024

Liquid
233
272
314
360
413

Vapor
141
142
143
146
148

Liquid
216
276
298
359
400

Vapor
136
138
139
141
143

Heating Operation
HPXB15-036

HPXB15-030

HPXB15-042
Liquid
240
281
325
372
428

Vapor
133
135
137
138
142

HPXB15-042

HPXB15-048
Liquid
228
265
304
348
405

Vapor
137
139
141
142
145

HPXB15-048

HPXB15-060
Liquid
231
269
315
370
415

Vapor
124
126
127
133
136

HPXB15-060

Temp. °F (°C)

Liquid

Vapor

Liquid

Vapor

Liquid

Vapor

Liquid

Vapor

Liquid

Vapor

Liquid

Vapor

20 (-6.6)
30 (-1.1)
40 (4.4)
50 (10.0)

288
306
325
344

60
75
90
105

270
297
325
353

67
84
100
117

234
257
318
322

62
80
93
103

340
350
353
358

65
72
83
101

313
330
346
366

60
73
87
101

245
287
332
347

55
66
82
99

Table 7
R410A Temperature/Pressure
Temperature
°F

Chart

Pressure
Psig

Temperature
°F

Pressure
Psig

Temperature
°F

Pressure
Psig

32
33

100.8
102.9

63
64

178.5
181.6

94
95

290.8
295.1

125
126

445.9
451.8

105.0

184.3

299.4

127

457.6

107.1

187.7

303.8

128

463.5

109.2

190.9

308.2

129

469.5

111.4

194.1

312.7

130

475.6

113.6

197.3

100

317.2

131

481.6

115.8

200.6

101

321.8

132

487.8

118.0

203.9

102

326.4

133

494.0

120.3

207.2

103

331.0

134

500.2

122.6

210.6

104

335.7

135

506.5

125.0

214.0

105

340.5

136

512.9

127.3

217.4

106

345.3

137

519.3

129.7

220.9

107

350.1

138

525.8

132.2

224.4

108

355.0

139

532.4

134.6

228.0

109

360.0

140

539.0

137.1

231.6

110

365.0

141

545.6

139.6

235.3

111

370.0

142

552.3

142.2

239.0

112

375.1

143

559.1

144.8

242.7

113

380.2

144

565.9

147.4

246.5

114

385.4

145

572.8

150.1

250.3

115

390.7

146

579.8

152.8

254.1

116

396.0

147

586.8

155.5

258.0

117

401.3

148

593.8

158.2

262.0

118

406.7

149

601.0

161.0

266.0

119

412.2

150

608.1

163.9

270.0

120

417.7

151

615.4

166.7

274.1

121

423.2

152

622.7

169.6

278.2

122

428.8

153

630.1

172.6

282.3

123

434.5

154

637.5

195.5

286.5

124

440.2

155

645.0

Page 18

Temperature
°F

Pressure
Psig

When an abnormal condition is detected, the module com-

Theoutdoorunitandindoorblowercycleondemandfrom
theroomthermostat.
Whenthethermostat
blowerswitchis
intheONposition,
theindoorbloweroperatescontinuously.
ThermostatOperation
Someoutdoorthermostats
incorporate
isolatingcontacts
andanemergency
heatfunction(whichincludes
anamber
indicatinglight).Thethermostat
isnotincluded
withtheunit
andmustbepurchased
separately,
EmergencyHeat(AmberLight)
Anemergency
heatfunction
isdesigned
intosomeroomthermostats.
Thisfeatureis applicable
whenisolation
oftheoutdoorunitis required,
orwhenauxiliary
electricheatisstaged
byoutdoor
thermostats,
Whentheroomthermostat
is placed
intheemergency
heatposition,
theoutdoor
unitcontrol
drcuit
is isolated
frompowerandfield-provided
relaysbypassthe
outdoor
thermostats,
Anamberindicating
lightsimultaneously
comesontoremind
thehomeowner
thatheisoperating
inthe
emergency
heatmode,
Emergencyheatis usuallyusedduringan outdoorunit
shutdown,
butitshouldalsobeusedfollowing
a poweroutageif powerhasbeenoffforoveranhourandtheoutdoor
temperature
is below50°F(10°C).Systemshouldbeleftin
theemergency
heatmodeatleastsixhoursto allowthe
crankcaseheatersufficienttimeto preventcompressor
slugging.
HighPressureSwitch
TheHPXB15
is equipped
withanauto-reset
highpressure
switchwhichis locatedon the liquidline.Thenormally
closedswitchopensthe compressorcircuitwhen dischargepressurerisesabove640+ 10psig(4412+ 69
kPa),The switchautomatically
closeswhendischarge
pressurefallsbelow448+ 10psig(3089+ 69kPa),
FilterDrier
Theunitis equipped
witha large-capacity
bifiowfilterdrier
whichkeepsthe systemcleananddry.If replacement
is
necessary,
orderanotheroflikedesignandcapacity.
The
replacement
filterdriermustbesuitable
forusewithR410A
refrigerant,
System Operation Monitor
The system operation monitor detects the most common
fault conditions in the air conditioning system,

municates the specific condition through its ALERT and
TRIP lights. The monitor is capable of detecting both mechanical and electrical system problems, See figure 18 for
the system operation monitor

A, IMPORTANT

System Operation Monitor

LED

"R
LED's

Figure

LED Functions
See table 8 for LED troubleshooting diagnostic codes.
Power LED (green) - indicates voltage within the range of
19-28VAC is present at the power connection of the monitor.
Alert LED (yellow) - communicates an abnormal system
condition through a unique flash code, The alert LED will
flash a number of times consecutively, pause and then repeat the process. The number of consecutive flashes, defined as the Flash Code, correlates to a particular abnormal
condition,
Trip LED (red) - indicates there is a demand signal from the
thermostat but no current to the compressor is detected by
the module,
TRIP and ALERT LEDs flashing at the same time indicates
that the control circuit voltage is too low for operation.
Reset ALERT flash code by removing 24VAC power from
monitor. Last ALERT flash code will display for 1 minute after monitor is powered on,

Page 19

System

Operation

Table 8
Monitor LED Troubleshooting

Codes

Status LED

Status LED Description

Status LED Troubleshooting

Information

Green "Power"

Module has power.

24MAC control power is present at the module terminal.

Red "Trip"

Thermostat demand signal
Y1 is present, but the compressor is not running.

1 Compressor protector is open.
2 Outdoor unit power disconnect is open.
3 Compressor circuit breaker or fuse(s) is open.
4 Broken wire or connector is not making contact.
5 Low pressure switch open if present in the system.
6 Compressor contactor has failed to close.
Low refrigerant charge.

Yellow "Alert"
Flash Code 1
(Does not apply to heat
pump or to two-stage
split systems)

Long Run Time
Compressor is running
tremely long run cycles

Yellow "Alert"
Flash Code 2

System Pressure Trip
Discharge or suction pressure out of limits or
compressor overloaded

_ High head pressure.
2 Condenser coil poor air circulation (dirty, blocked, damaged).
3 Condenser fan is not running.
4 Return air duct has substantial leakage.
5 If low pressure switch is present, check Flash Code 1 information.

Yellow "Alert"
Flash Code 3

Short Cycling
Compressor is
running
only briefly

I Thermostat demand signal is intermittent.
2 Time delay relay or control board is defective.
3 If high pressure switch is present, check Flash Code 2 information.
4 If low pressure switch is present, check Flash Code 1 information.

Yellow

ex-

"Alert"

Flash Code 4

Locked

Yellow "Alert"
Flash Code 5

Open Circuit

Yellow "Alert"
Flash Code 6
Yellow "Alert"
Flash Code 7
Yellow "Alert"
Flash Code 8

Rotor

2 Evaporator blower is not running.
3 Evaporator coil is frozen.
4 Faulty metering device.
5 Condenser coil is dirty
6 Liquid line restriction (filter drier blocked if present)
7 Thermostat is malfunctioning.

_ Run capacitor has failed.
2 Low line voltage (contact utility if voltage at disconnect
3 Excessive liquid refrigerant in the compressor.
4 Compressor bearings are seized.
Outdoor unit power disconnect is open.
2 Unit circuit breaker or fuse(s) is open.

is low).

Open Start Circuit
Current only in run circuit

3 Unit contactor has failed to close.
4 High pressure switch is open and requires manual reset.
5 Open circuit in compressor supply wiring or connections.
6 Unusually long compressor protector reset time due to extreme ambient temperature.
7 Compressor windings are dama0ed.
_ Run capacitor has failed.
2 Open circuit in compressor start wiring or connections.
3 Compressor start windinq is damaqed.

Open Run Circuit
Current only in start circuit

1 Open circuit in compressor start wiring or connections.
2 Compressor start windinq is damaqed.

Welded Contactor
Compressor always runs

I Compressor contactor failed to open.
2 Thermostat demand siqnal not connected to module.

Yellow "Alert"
Low Voltage
1 Control circuit transformer is overloaded
Flash Code 9
Control circuit < 17VAC
2 Low line volta qe (contact utility if volta qe at disconnect is low.)
• Flash code number corresponds to a number of LED flashes, followed by a pause, and then repeated.
• TRIP and ALERT LEDs flashing at the same time indicates that the control circuit voltage is too low for operation.
• Reset ALERT flash code by removing 24VAC power from monitor. Last ALERT flash code will display for 1 minute after monitor is powered on.

Defrost Control
The defrost control board includes the combined funcThe defrost system includes two components:
• a defrost thermostat
• a defrost control

tions of a time/temperature
relay, time delay, diagnostic

defrost control, defrost
LEDs, and a terminal strip

for field wiring connections,

See figure 19.

Defrost Thermostat

The control provides automatic switching from normal
heating operation to defrost mode and back. During compressor cycle (call for defrost), the control accumulates
compressor run times at 30, 60, or 90 minute field adjustable intervals. If the defrost thermostat is closed when the

The defrost thermostat is located on the liquid line between the check/expansion
valve and the distributor.
When the defrost thermostat senses 42°F (5.5°C) or cooler, its contacts close and send a signal to the defrost control board to start the defrost timing. It also terminates defrost when the liquid line warms up to 70°F (21°C),

selected compressor run time interval ends, the defrost
relay is energized and defrost begins,

Page 20

DefrostControlTimingPins
Eachtimingpinselectionprovidesa differentaccumulatedcompressorruntimeperiodduringonethermostat
runcycle.Thistimeperiodmustoccurbeforea defrost
cycleis initiated.Thedefrostintervalcanbeadjustedto
30(T1),60 (T2),or 90 (T3)minutes.Seefigure19,The
defrosttimingjumperis factory-installedto providea
90-minutedefrostinterval.Ifthetimingselectorjumperis
notin place,the controldefaultstoa 90-minutedefrost
interval,Themaximumdefrostperiodis 14minutesand
cannotbeadjusted,
A TESToptionisprovidedfortroubleshooting,
TheTEST
modemaybestartedanytimethe unitis in theheating
modeandthe defrost thermostatis closedor jumpered.Ifthejumperis intheTESTpositionatpower-up,
the
controlwillignorethetestpins,Whenthejumperisplaced
acrosstheTESTpinsfortwoseconds,
thecontrolwillenter
thedefrostmode,If thejumperis removedbeforeanadditional5-secondperiodhaselapsed(7secondstotal),the
unitwillremainindefrostmodeuntilthedefrostthermostat
opensor 14minuteshavepassed.If thejumperis notremoveduntil after the additional5-secondperiodhas
elapsed,thedefrostwillterminateandthetestoptionwill
notfunctionagainuntilthejumperis removedandreapplied,
CompressorDelay
The defrost board has a built-in function to reduce occasional sounds that may occur while the unit is cycling in and out
of the defrost mode, The compressor will be cycled off for 30
seconds going in and out of the defrost mode.
NOTE - The 30 second off cycle is not functional when jumpering the TEST pins.

minals to accommodate the addition of a field-provided low
pressure or loss of charge pressure switch, See figure 19.
This feature is available on all units,
During a single demand cycle, the defrost control will lock
out the unit after the fifth time that the circuit is interrupted
by any pressure switch that is wired to the control board. In
addition, the diagnostic LEDs will indicate a locked out
pressure switch after the fifth occurrence of an open pressure switch, See table 9. The unit will remain locked out until power is broken then remade to the control or until the
jumper is applied to the TEST pins for 0.5 seconds,
NOTE - The defrost control board ignores input from the
low pressure switch terminals during the TEST mode, during the defrost cycle, during the 90-second start-up period,
and for the first 90 seconds each time the reversing valve
switches heat/cool modes. If the TEST pins are jumpered
and the 5-minute delay is being bypassed, the LOPS
terminal signal is not ignored during the 90-second
start-up period.
Ambient Thermistor & Service Light Connection
The defrost control board provides terminal connections
for the ambient thermistor and a service light. The thermistor compensates for changes in ambient temperature
which might cause thermostat droop, The service light
thermostat provides a signal which activates the room thermostat service light during periods of inefficient operation,
Diagnostic

LEDs

The defrost board uses two LEDs for diagnostics, The
LEDs flash a specific sequence according to the diagnosis,
Table

Defrost Control Board Diagnostic

The timed-off delay is five minutes long. The delay helps
protect the compressor from short-cycling in case the power
to the unit is interrupted or a pressure switch opens, The
delay is bypassed by placing the timer select jumper across
the TEST pins for 0,5 seconds.
Pressure Switch Circuits
The defrost control includes two pressure switch circuits.
The high pressure switch ($4) is factory-connected to the
board's HI PS terminals. The board also includes LOPS ter-

LED

LED 1

Mode

Time Delay

9
LED 2

Normal operation /
power to board
Board failure or no
power
Board failure

Synchronized
Flash with LED
z
Off

Synchronized
Flash with LED
I
Off

High pressure switch
open
Low pressure switch open

Flash

Pressure switch lockout

Off

Anti-short-cycle /
5-minute delay

Alternating
Flash with
IFD2

Alternating
Flash with
IFD1

Page 21

Defrost
FAN

Control

Board

O
U

[]

HI PS

(Factory-wired)

Optional
Pressure
Switch

Ambient
Thermistor
Terminals

Optional
Pressure
Switch
Terminals

K2 RELAY]

(Remove
factoryinstalled jumper
to install
LO

(Field-provided
and installed -jumper

Service
Light
Terminals

High Pressure
Switch
Terminals

Pressure Switch
Wiring Connections

High
Pressure
Switch

===Wl

removed)

pressure

K3 RELAY

DEFROST
INTERVAL
TIMING
PINS
HOT

switch.)

Defro_

L0-PS

Thermostat

24V
Terminal
Strip

D,A NOST,°

Reversing
Valve

LEDs
O TST

O-0UT

o PS_
oDF
oC
oR
o 0

Figure

HOT

o YI

19
6 - Check amp-draw on outdoor fan motor.
7-

Inspect drain holes in coil compartment

base and

clean if necessary.

AWARNING

NOTE - If owner complains of insufficient cooling, the unit
should be gauged and refrigerant charge checked. Refer to
section on refrigerant charging in this instruction.
Indoor Coil
1 - Clean coil if necessary.
2 - Check connecting lines, joints and coil for evidence of
oil leaks.

Maintenance and service must be performed by a qualified installer or service agency. At the beginning of each
cooling or heating season, the system should be checked
as follows:

3 - Check condensate line and clean if necessary.
Indoor Unit
1 - Clean or change filters,

Outdoor Unit

2 - Lennox blower motors are prelubricated and permanently sealed, No more lubrication is needed.

1 - Clean and inspect outdoor coil (may be flushed with a
water hose). Ensure power is off before cleaning.

3 - Visually inspect all connecting lines, joints and coils for
evidence of oil leaks.

3 - Adjust blower speed for cooling, Measure the pressure
drop over the coil to determine the correct blower CFM
Refer to the unit information service manual for pressure
drop tables and procedure,
4 - Belt Drive Blowers - Check belt for wear and proper
tension,

4 - Check all wiring for loose connections.

5 - Check all wiring for loose connections,

5 - Check for correct voltage at unit (unit operating).

6 - Check for correct voltage at unit,

2 - Outdoor unit fan motor is prelubricated and sealed. No
further lubrication is needed.

Page 22

7 - Checkamp-draw
onblowermotor.

cause the outdoor unit to work harder and use more ener-

RefertotheEngineering
Handbook
foroptionalaccessoriesthatmayapplytothisunit,Thefollowingmayor may
notapply:
• Lossof ChargeKit
• HighPressureSwitcKit
• Compressor
Monitor
• Compressor
Crankcase
Heater
• HailGuards
• Mounting
Bases
• TimedOffControl
• Stand-off
Kit
• SoundCover
• LowAmbientKit
• MonitorKit
Inordertoensurepeakperformance,
yoursystemmustbe
properlymaintained.
Cloggedfiltersandblockedairflow
preventyourunitfromoperating
at itsmostefficientlevel,
AskyourLennoxdealerto showyouwhereyourindoor
unit'sfilteris located.It will be eitherat the indoorunit
(installed
internalorexternalto thecabinet)orbehinda returnairgrilleinthewallorceiling.Checkthefiltermonthly
andcleanorreplaceitas needed,
Disposable
filtersshouldbereplacedwitha filterof the
sametypeandsize,If youareunsureaboutthefilteryou
needforyoursystem,callyourLennoxdealerfor assistance.

A IMPORTANT

gy. Keep shrubbery trimmed away from the unit and periodically check for debris which may have collected around
the unit,
Heat Pump Operation
Your new Lennox heat pump has several characteristics
that you should be aware of:
Your heat pump satisfies heating demand by delivering
large amounts of warm air into the living space. This is quite
different from gas- or oil-fired furnaces or an electric furnace which deliver lower volumes of considerably hotter air
to heat the space,
Do not be alarmed if you notice frost on the outdoor coil in
the winter months. Frost develops on the outdoor coil during the heating cycle when temperatures are below 45°F
(7°C). An electronic control activates a defrost cycle lasting
5 to 15 minutes at preset intervals to clear the outdoor coil
of the frost. During the defrost cycle, you may notice steam
rising from the outdoor unit, This is a normal occurrence.
The thermostat may engage auxiliary heat during the defrost cycle to satisfy a heating demand; however, the unit
will return to normal operation at the conclusion of the defrost cycle.
Your Lennox HPXB15 heat pump is equipped with a compressor crankcase heater which protects the compressor
from refrigerant slugging during cold weather operation. If
power to your unit has been interrupted for several hours
or more, set the room thermostat selector to the "Emergency Heat" setting to obtain temporary heat without the risk
of serious equipment damage, In this operating mode, all
heating demand will be satisfied by auxiliary heat. Compressor operation is locked out during Emergency Heat operation. After a six-hour compressor crankcase heater
warm-up period, the thermostat can be switched to the
"Heat" setting and normal operation will resume.
Thermostat

Many indoor units are equipped with reusable foam filters.
These filters can be cleaned with a mild soap and water
solution, Rinse the filter thoroughly and let it dry completely
before it is returned to the unit or grille,
The filter and all access panels must be in place any
time the unit is in operation.
Your system may be equipped with an electronic air cleaner which will provide respiratory relief by removing up to 90
percent of all airborne particles which pass through it. If it
is, ask your dealer to instruct you on its maintenance,
Your indoor evaporator coil is equipped with a drain pan to
collect condensate formed as your system removes humidity from the inside air. Have your dealer show you where
the main condensate drain (and auxiliary drain, if applicable) runs and how to check the drain for any obstruction,
It is also very important to provide unrestricted airflow to the
outdoor unit, Leaves, trash or shrubs crowding the unit

Operation

Though your thermostat may vary somewhat from the description below, its operation will be similar,
Temperature Setting Levers
Most heat pump thermostats have two temperature selector levers: one for heating and one for cooling, Set the levers or dials to the desired temperature setpoints for both
heating and cooling. Avoid frequent temperature adjustment; turning the unit off and back on before pressures
equalize puts stress on the unit compressor.
Fan Switch
In AUTO or INT (intermittent) mode, the blower operates
only when the thermostat calls for heating or cooling. This
mode is generally preferred when humidity control is a
priority. The ON or CONT mode provides continuous indoor blower operation, regardless of whether the compressor or auxiliary heat are operating, This mode is required
when constant air circulation or filtering is desired.

Page 23

System Switch
Set the system switch for heating, cooling or auto operation, The auto mode allows the heat pump to automatically
switch from heating mode to cooling mode to maintain predetermined comfort settings, Many heat pump thermostats
are also equipped with an emergency heat mode which
locks out heat pump operation and provides temporary
heat supplied by the auxiliary heat,
Indicating Light

and cooling, Refer to the user's information manual provided with your particular thermostat for operation details.
Preservice Check
If your system fails to operate, check the following before
calling for service:
• Check to see that all electrical disconnect switches
are ON,
• Make sure the room thermostat temperature selector
is properly set,

Most heat pump thermostats have an amber light which indicates when the heat pump is operating in the emergency
heat mode.

• Make sure the room thermostat system switch is properly set.

Temperature Indicator
The temperature indicator displays the actual room temperature,

• Replace any blown fuses, or reset circuit breakers.
• Make sure unit access panels are in place.

Programmable Thermostats
Your Lennox system may be controlled by a programmable
thermostat. These thermostats provide the added feature
of programmable time-of-day setpoints for both heating

Start-up

Job Name
Job Location

• Make sure air filter is clean,
• Locate unit model number and have it handy before
calling,

and Performance
Job No,

Check

City

Installer
Unit Model No,

List

Date
State

City

State
Service Technician

Serial No.

Nameplate Voltage
Rated Load Ampacity
Maximum Fuse or Circuit Breaker

Indoor Filter Clean? []

Electrical Connections Tight? []
Indoor Blower RPM
Cooling
Liquid Line Pressure
Heating
Liquid Line Pressure
Refrigerant Lines:

Outdoor Fan

Compressor

Supply Voltage (Unit Off) __

S.R Drop Over Indoor (Dry)

Vapor Pressure
Vapor Pressure
Leak Checked? []

Properly Insulated?

[]

Outdoor Coil Entering Air Temp.
Refrigerant Charge Checked?

[]

Refrigerant Charge Checked?
Outdoor Fan Checked?

[]
[]

Service Valves Fully Opened? []
Voltage With Compressor
Operating
-Service Valve Caps Tight? []
Thermostat
Sequence of Operation
Heating Correct []
Cooling Correct []
Calibrated?
[]
Properly Set? []
Level?

Page 24

[]

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LENNOX Air Conditioner/heat Pump(outside Unit) Manual L0806498

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