Lennox Merit 10HPB, 10HPB18, 10HPB24, 10HPB30, 10HPB36 Installation Instructions Manual

Page 1

504,828M

*P504828M*

06/04

*2P0604*

2003 Lennox Industries Inc.

Dallas, Texas, USA

®

10HPB Outdoor Units

Lennox Merit® Series 10HPB outdoor units are approved
and warranted only for installation with specially matched
indoor coils, line sets, and refrigerant control systems as
designated by Lennox. Refer to Lennox Engineering
Handbook for expansion valve kits which must be ordered
separately.

Shipping and Packing List

1 − Assembled 10HPB outdoor unit

1 − Coupling (18, 24 and 30)

Check unit for shipping damage. Consult last carrier imme­diately if damage is found.

WARNING

Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person­al injury or loss of life. Installation and service must
be performed by a qualified installer or service
agency.

IMPORTANT

The Clean Air Act of 1990 bans the intentional vent­ing of refrigerant (CFC’s and HCFC’s) as of July 1,

1992. Approved methods of recovery, recycling or
reclaiming must be followed. Fines and/or incarcera­tion may be levied for noncompliance.

INSTALLATION
INSTRUCTIONS

10HPB Series Units

HEAT PUMP UNITS

1−1/2 through 5 tons
504,828M
06/04

Supersedes 02/04

Table of Contents

10HPB Outdoor Units 1. . . . . . . . . . . . . . . . . . . . . . . . . . .

Shipping & Packing List 1. . . . . . . . . . . . . . . . . . . . . . . . .

General Information 1. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Unit Dimensions 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Setting the Unit 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Electrical 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Refrigerant Piping 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Refrigerant Metering Device 10. . . . . . . . . . . . . . . . . . . .

Manifold Gauge Set 10. . . . . . . . . . . . . . . . . . . . . . . . . . .

Service Valves 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Leak Testing 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Evacuation 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Start−Up 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Charging 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

System Operation 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Defrost System 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Maintenance 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Optional Accessories 18. . . . . . . . . . . . . . . . . . . . . . . . . .

Start−Up and Performance Check List 18. . . . . . . . . . . .

RETAIN THESE INSTRUCTIONS

FOR FUTURE REFERENCE

General Information

These instructions are intended as a general guide and do
not supersede national or local codes in any way. Authori­ties having jurisdiction should be consulted before instal­lation.

WARNING

This product and/or the indoor unit it is matched with
may contain fiberglass wool.

Disturbing the insulation during installation, mainte­nance, or repair will expose you to fiberglass wool
dust. Breathing this may cause lung cancer. (Fiber­glass wool is known to the State of California to
cause cancer.)

Fiberglass wool may also cause respiratory, skin,
and eye irritation.

To reduce exposure to this substance or for further
information, consult material safety data sheets
available from address shown below, or contact your
supervisor.

Lennox Industries Inc.

P.O. Box 799900
Dallas, TX 75379−9900

Litho U.S.A.

Page 2

10HPB Unit Dimensions − inches (mm)

Side View

vapor &

liquid line

connection

discharge air

Side View

Top View

A

outdoor

coil fan

compressor

inlet

air

B

24-1/4

(616)

2-3/4 (70)

24-1/4

(616)

electrical

inlets

optional unit
stand-off kit (4)
(field−installed)

4-3/8
(111 )

6-3/8
(162)

6-3/8
(162)

Top View Base Section

3/4

(19)

4-3/8

(111 )

4-3/8

(111)

4-3/8
(111 )

4-3/8
(111 )

4-3/8
(111 )

coil drain outlets

(around perimeter of base)

optional unit
stand-off kit (4)
(field−installed)

liquid line

connection

vapor line

connection

2 (51)

COMPRESSOR

inlet

air

inlet

air

inlet

air

Model No.

A B

10HPB18

in. 25 24-1/4

10HPB18

10HPB24

mm 635 616

in. 29 28-1/4

10HPB30

mm 737 718

10HPB36
10HPB42

in. 33 32-1/4

10HPB42

10HPB48
10HPB60

mm 838 819

Page 3

Setting the Unit

CAUTION

In order to avoid injury, take proper precaution when
lifting heavy objects.

CAUTION

Sharp sheet metal edges can cause injury. When
installing the unit, avoid accidental contact with
sharp edges.

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 1 for
installation clearances.

see

note

Installation Clearances

see

note

NOTE − A service clearance of 30" (762 mm) must be main­tained on one of the sides adjacent to the control box. Clear­ance to one of the other three sides 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).

see

note

NOTE − A clearance of 24" (610 mm) must be maintained
between two units.
NOTE − 48" (1219 mm) clearance required on top
of unit. Maximum soffit overhang is 36" (914 mm).

see

note

Figure 1

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.

2 − Install the unit high enough above the ground or roof to

allow adequate drainage of defrost water and prevent
ice buildup.

3 − In heavy snow areas, do not locate the unit where drift-

ing will occur. The unit base should be elevated above
the depth of average snows.

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.

4 − When installed in areas where low ambient tempera-

tures exist, locate unit so winter prevailing winds do not
blow directly into outdoor coil.

5 − Locate unit away from overhanging roof lines which

would allow water or ice to drop on, or in front of, coil or
into unit.

Slab Mounting − Figure 2

When installing a unit at grade level, the top of the slab
should be high enough above the grade so that water from
higher ground will not collect around the unit. See figure 2.
Slab should have a slope tolerance away from the building
of 2 degrees or 2 inches per 5 feet (51 mm per 1524 mm).
This will prevent ice from building up under the unit during a
defrost cycle. Refer to roof mounting section for barrier
construction if unit must face prevailing winter winds.

Figure 2

Slab Mounting At Ground Leve

l

discharge air

Mounting slab must slope
away from building.

ground level

structure

Roof Mounting − Figure 3

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.

Page 4

If unit coil cannot be mounted away from prevailing winter
winds, a wind barrier should be constructed. Size barrier at
least the same height and width as outdoor unit. Install bar­rier 24 inches (610 mm) from the sides of the unit in the di­rection of prevailing winds.

wind barrier

inlet air

inlet air

inlet air

inlet air

prevailing winter winds

Rooftop Application

Wind Barrier Construction

Figure 3

Electrical

WARNING

Unit must be grounded in accordance with national
and local codes.
Electric Shock Hazard.
Can cause injury or death.

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.

NOTE − To facilitate conduit, a hole is in the bottom of
the control box. Connect conduit to the control box us
ing a proper conduit fitting.

NOTE − 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 4 for field wiring
diagram.

NOTE − A complete unit wiring diagram is located in
side the unit control box cover.

3 − Install room thermostat (ordered separately) on an in-

side 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 effected
by sunlight, drafts or vibrations.

4 − Install voltage wiring from outdoor to indoor unit and

from thermostat to indoor unit. See figures 5 and 6.

Page 5

Typical Wiring Field Wiring Diagram

Figure 4

*

*

*May be optional

R

C

W1

Y1

O

G

R

C

W1

W2

W3

G

reversing valve

10HPB and Blower Unit

Thermostat Designations

(Some connections may not apply.

Refer to specific thermostat and indoor unit.)

Thermostat

Indoor

Unit

R

C

W1

Y1

O

Outdoor

Unit

Figure 5

power

power

common common

1st. stage aux. heat

1st. stage aux. heat

indoor blower

compressor

R

C

W1

Y1

O

G

R

C

W1

W2

W3

G

10HPB and Blower Unit

Thermostat Designations

(with auxiliary heat)

(Some connections may not apply.

Refer to specific thermostat and indoor unit.)

Thermostat

Indoor

Unit

Outdoor

Unit

E

R

C

W1

Y1

O

reversing valve

indoor blower

compressor

power

power

common common

1st. stage aux. heat

1st. stage aux. heat

emergency heat

Figure 6

Page 6

Refrigerant Piping

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. Refer to Refrigerant Piping Guide
(Corp. 9351−L9) for proper size, type, and application of
field−fabricated lines. Valve sizes are also listed in table 1.

Table 1

Refrigerant Line Sets

Valve Field Size

Connections

Recommended Line Set

Model

Liquid

Line

Vapor

Line

Liquid

Line

Vapor

Line

L15

Line Sets

−18

3/8 in.

(10 mm)

5/8"

(15.9 mm)

5/16"*

(7.9 mm)

5/8"

(15.9

mm)

L15−21

15 ft. − 50 ft.

(4.6 m − 15

m)

−24

−30

3/8 in.

(10 mm)

3/4"

(19 mm)

5/16"*

(7.9 mm)

3/4"

(19 mm)

L15−31

15 ft. − 50 ft.

(4.6 m − 15 m)

−36

3/8 in.

(10 mm)

3/4"

(19 mm)

3/8"

(9.5 mm)

3/4"

(19 mm)

L15−41

15 ft. − 50 ft.

(4.6 m − 15 m)

−42

−48

3/8 in.

(10 mm)

7/8"

(22.2 mm)

3/8"

(9.5 mm)

7/8"

(22.2

mm)

L15−65

15 ft. − 50 ft.

(4.6 m − 15 m)

−60

3/8 in.

(10 mm)

1−1/8"

(28.5 mm)

3/8"

(9.5 mm)

1−1/8"

(28.5

mm)

Field

Fabricated

*Use reducer supplied in bag assembly

NOTE − Units are designed for line sets of up to fifty feet (15
m). For applications longer than fifty feet, consult the Len-

nox Refrigerant Piping Guide (Corp. 9351−L9). Select line
set diameters from table 1 to ensure that oil returns to the
compressor.

Installing Refrigerant Line

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.

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

1- Placement − Be aware some localities are adopting

sound ordinances based on how noisy the unit is from
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.

2- Line Set Isolation − The following illustrations demon-

strate procedures which ensure proper refrigerant line
set isolation. Figure 7 shows how to install line sets on
vertical runs. Figure 8 shows how to install line sets on
horizontal runs. Figure 9 shows how to make a transition
from horizontal to vertical. Finally, figure 10 shows how
to place the outdoor unit and line set.

Page 7

Installing Vertical Runs of Refrigerant Piping

(new construction shown)

PVC Pipe

Fiberglass

Insulation

Caulk

Outside Wall

Vapor Line

(wrapped with Armaflex)

Liquid Line

IMPORTANT - Refrigerant

lines must not contact

structure.

Outside Wall

Inside Wall

Liquid LineVapor Line

IMPORTANT - Refrigerant

lines must not contact wall.

Wood Block

Between Studs

Strap

Sleeve

Wood Block

Strap

Sleeve

Wire Tie

Wire Tie

Wire Tie

NOTE - Similar installation practices should be used if
line set is to be installed on exterior of outside wall.

Figure 7

Page 8

Installing Horizontal Runs of Refrigerant Piping

8 feet

8 feet

Metal Sleeve

Strapping Material (around vapor line only)

Tape or Wire Tie

Wire Tie

(around vapor line only)

Floor Joist or

Roof Rafter

Tape or Wire Tie

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

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

Floor Joist or Roof Rafter

Figure 8

Page 9

Transitioning from Vertical to Horizontal

Runs of Refrigerant Piping

Liquid Line

Vapor Line

Wrapped in

Armaflex

Strap Liquid Line

To Vapor Line

Metal

Sleeve

Anchored Heavy

Nylon Wire Tie

Automotive

Muffler-Type

Hanger

Wall
Stud

Wall
Stud

Liquid Line

Vapor Line

Wrapped in

Armaflex

Strap Liquid Line

To Vapor Line

Metal

Sleeve

Figure 9

Outside Unit Placement and Installation

Figure 10

Install unit away from windows .

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

Page 10

Brazing Connection Procedure

1 − Cut ends of the refrigerant lines square (free from nicks

or dents). Debur the ends. The pipe must remain
round, do not pinch end of the line.

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
silver alloy for copper−to−brass or copper−to−steel braz­ing) which are rated for use with HCFC22 refrigerant.
Wrap a wet cloth around the valve body and the copper
tube stub. Braze the line set to the service valve.

4 − Wrap a wet cloth around the valve body and copper

tube stub to protect it from heat damage during braz­ing. Wrap another wet cloth underneath the valve body
to protect the base paint.

NOTE − The tube end must stay bottomed in the fitting
during final assembly to ensure proper seating, sealing
and rigidity.

5 − Install a field−provided thermal expansion valve (ap-

proved for use with HCFC22 refrigerant) in the liquid
line at the indoor coil.

Refrigerant Metering Device

10HPB units are used in check expansion valve systems
only. See the Lennox Engineering Handbook for approved
TXV match-ups and application information.

Check expansion valves equipped with either Chatleff or
flare−type fittings are available from Lennox. Refer to the
Engineering Handbook for applicable expansion valves
for use with specific match-ups. See table 2 for applicable
check expansion valve kits.

If you install a check expansion valve with an indoor
coil that includes a fixed orifice, remove the orifice be­fore the check expansion valve is installed.

IMPORTANT

Failure to remove RFC orifice when installing an ex­pansion valve on the indoor coil will result in improp­er operation and damage to the system.

Table 2

Indoor Check And Expansion Valve Kits

Model Kit Number

10HPB18
10HPB24
10HPB30
10HPB36

LB−85759F

10HPB42
10HPB48
10HPB60

LB−85759G

See figure 11 for installation of the check expansion valve.

Metering Device Installation

expansion

valve

o−ring

o−ring

strainer

liquid line

stub

distributor

Figure 11

Manifold Gauge Set

When checking the unit charge, use a manifold gauge set
that is equipped with low loss" hoses. Do not use a man­ifold gauge set with anything other than a low loss" hose.
See figure 12 for manifold gauge connections.

Page 11

Figure 12

10HPB Manifold Gauge Connections (Cooling Cycle)

outdoor

coil

defrost thermostat

expansion/

check valve

biflow

filter / drier

to

HCFC−22

drum

low

pressure

high

pressure

compressor

reversing valve

vapor

line

valve

muffler

Note − Arrows indicate the direction of refrigerant flow.

vapor

service

port

expansion/check

valve

Indoor Unit

Outdoor Unit

liquid line

service

port

gauge manifold

distributor

indoor

coil

Service Valves

The liquid line and vapor line service valves (figures 13 and

14) and gauge ports are used for leak testing, evacuating,
charging and checking charge. See table 3 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
primary leak seal.

Table 3

Torque Requirements

Part 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

IMPORTANT

Service valves are closed to the outdoor unit and
open to line set connections. Do not open the valves
until refrigerant lines have been leak tested and
evacuated. All precautions should be exercised to
keep the system free from dirt, moisture and air.

To Access Schrader Port:

1 − Remove service port cap with an adjustable wrench.

2 − Connect gauge to the service port.

3 − When testing is completed, replace service port cap.

Tighten finger tight, then an additional 1/6 turn.

To Open Liquid or Vapor Line Service Valve:

1 − Remove stem cap with an adjustable wrench.

2 − Use a service wrench with a hex head extension to back

the stem out counterclockwise as far as it will go.

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.

To Close Liquid Line Service Valve:

1 − Remove stem cap with an adjustable wrench.

2 − Use a service wrench with a hex head extension to turn

the stem clockwise to seat the valve. Tighten firmly.

NOTE − Use a 3/16" hex head extension for liquid line
sizes or a 5/16" extension for vapor line sizes.

3 − Replace the stem cap. Tighten finger tight, then tighten

an additional 1/6 turn.

Ball−Type Vapor Line Service 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 14.

Page 12

The ball valve is equipped with a service port with a factory−
installed Schrader valve. A service port cap protects the
Schrader valve from contamination and assures a leak−
free seal.

Service Valve

(Valve Closed)

Schrader valve open

to line set when valve is

closed (front seated)

service

port

service

port cap

stem cap

insert hex

wrench here

(valve front seated)

to outdoor coil

to indoor coil

Service Valve

(Valve Open)

Schrader

valve

service

port

service port

cap

insert hex

wrench here

to indoor coil

to outdoor coil

stem cap

Figure 13

Vapor Line (Ball Type) Service Valve

(Valve Open)

Schrader

valve

stem cap

To open: rotate stem counter-clockwise 90.

To close: use adjustable wrench and

rotate stem clockwise 90.

ball

(shown open)

service port

cap

service

port

field side

unit side

stem

Figure 14

Leak Testing

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

WARNING

Danger of fire. Bleeding the refrigerant
charge from only the high side may re­sult in the low side shell and suction
tubing being pressurized. Appplication
of a brazing torch while pressurized
may result in ignition of the refrigerant
and oil mixture − check the high and low
pressures before unbrazing.

WARNING

Refrigerant can be harmful if it is inhaled. Refrigerant
must be used and recovered responsibly.

Failure to follow this warning may result in personal
injury or death.

WARNING

Danger of explosion: Can cause equip­ment damage, injury or death. Never
use oxygen to pressurize a refrigera­tion or air conditioning system. Oxygen
will explode on contact with oil and
could cause personal injury.

WARNING

Danger of explosion: Can cause equipment damage,
injury or death. When using a high pressure gas
such as dry nitrogen to pressurize a refrigeration or
air conditioning system, use a regulator that can
control the pressure down to 1 or 2 psig (6.9 to 13.8
kPa).

Using an Electronic Leak Detector or Halide

1 − Connect a cylinder of HCFC-22 to the center port of the

manifold gauge set.

2 − With both manifold valves closed, open the valve on

the HCFC-22 cylinder (vapor only).

3 − Open the high pressure side of the manifold to allow

the HCFC-22 into the line set and indoor unit. Weigh in
a trace amount of HCFC-22. [A trace amount is a maxi-
mum of 2 ounces (57 g) or 3 pounds (31 kPa) pres­sure.] Close the valve on the HCFC-22 cylinder and the
valve on the high pressure side of the manifold gauge
set. Disconnect the HCFC-22 cylinder.

4 − Connect a cylinder of nitrogen with a pressure regulat-

ing valve to the center port of the manifold gauge set.

Page 13

5 − Connect the manifold gauge set high pressure hose to

the vapor valve service port. (Normally, the high pres-

sure 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.)

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.

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 HCFC-22
mixture. Correct any leaks and recheck.

Evacuation

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.

IMPORTANT

Use a thermocouple or thermistor electronic vacuum
gauge that is calibrated in microns. Use an instrument
that reads from 50 microns to at least 10,000 microns.

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

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 the vacuum

pump.

5 − Evacuate the line set and indoor unit to an absolute

pressure of 23,000 microns (29.01 inches of mercu­ry). During the early stages of evacuation, it is desir­able to close the manifold gauge valve at least once to
determine if there is a rapid rise in absolute pressure.
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 cylin-

der 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.

CAUTION

Danger of Equipment Damage.
Avoid deep vacuum operation. Do not use compres­sors to evacuate a system.
Extremely low vacuums can cause internal arcing
and compressor failure.
Damage caused by deep vacuum operation will void
warranty.

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
HCFC-22 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 HCFC-22 cylinder and remove
the manifold gauge set.

Start−Up

IMPORTANT

If unit is equipped with crankcase heater, it should be
energized 24 hours before unit start−up to prevent
compressor damage as a result of slugging.

1 − Rotate fan to check for frozen bearings or binding.

2 − Inspect all factory and field-installed wiring for loose

connections.

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 tight-

en 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.

Page 14

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.

7 − Recheck voltage while the unit is running. Power must

be within range shown on the nameplate.

Charging

The unit is factory charged with the amount of HCFC-22 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 4 for refrigerant charge adjustment. A blank space is
provided on the nameplate to list the actual field charge.

Table 4

Liquid Line

Set Diameter

Oz. per 5 ft. (g per 1.5 m) adjust

from 15 ft. (4.6 m) line set*

5/16 in. (8 mm) 2 ounce per 5 ft. (57g per 1.5 m)

3/8 in. (9.5 mm) 3 ounce per 5 ft. (85g per 1.5 m)

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

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 deter-

mined by the unit’s refrigerant metering device and the out­door ambient temperature.

Measure the liquid line temperature and the outdoor ambi­ent temperature as outlined below:

1 − Close manifold gauge set valves. Connect the man-

ifold gauge set to the service valves:

 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 HCFC-22.

2 − Set the room thermostat to call for heat. This will create

the necessary load for properly charging the system in
the cooling cycle.

3 − Use a digital thermometer to record the outdoor ambi-

ent temperature.

4 − When the heating demand has been satisfied, switch

the thermostat to cooling mode with a set point of 68F
(20C). When pressures have stabilized, use a digital
thermometer to record the liquid line temperature.

5 − The outdoor temperature will determine which charg-

ing method to use. Proceed with the appropriate charg­ing procedure.

Weighing in the Charge TXV Systems –

Outdoor Temp < 65F (18C)

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.

1 − Recover the refrigerant from the unit.

2 − Conduct a leak check, then evacuate as previously

outlined.

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 Method

Outdoor Temp. < 65°F (18°C)

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 200−250 psig
(1379−1724 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 200−250 psig (1379−1724 kPa) range.
See figure 15.

Blocking Outdoor Coil

cardboard or

plastic sheet

Outdoor coil should be

blocked one side

at a time with cardboard

or plastic sheet until proper

testing pressures

are reached.

Figure 15

1 − With the manifold gauge hose still on the liquid service

port and the unit operating stably, use a digital ther-

mometer to record the liquid line temperature.
2 − At the same time, record the liquid line pressure reading.
3 − Use a temperature/pressure chart for HCFC-22 to de-

termine the saturation temperature for the liquid line

pressure reading.

4 − Subtract the liquid line temperature from the saturation

temperature (according to the chart) to determine sub-

cooling. (Saturation temperature − Liquid line tem-

perature = Subcooling)

Page 15

5 − Compare the subcooling value with those in table 5. If

subcooling is greater than shown, recover some refrig­erant. If subcooling is less than shown, add some re­frigerant.

Table 5

Subcooling Values

Model

Subcooling Temp. _F (_C)

10HPB18 5 (2.8)
10HPB24 7 (3.9)
10HPB30 9 (5)
10HPB36 11 (6.1)
10HPB42 7 (3.9)
10HPB48 8 (4.4)
10HPB60 10 (5.6)

Charging Using Normal Operating Pressures

and the Approach Method

Outdoor Temp. >

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.
3 − Compare stabilized pressures with those provided in

table 6, Normal Operating Pressures." Minor varia-

tions in these pressures may be expected due to differ-

ences in installations. Significant differences could

mean that the system is not properly charged or that a

problem exists with some component in the system.

Pressures higher than those listed indicate that the

system is overcharged. Pressures lower than those

listed indicate that the system is undercharged. Verify

adjusted charge using the approach method.

Table 6

Normal Operating Pressures

Outdoor

10HPB18 10HPB24 10HPB30 10HPB36 10HPB42 10HPB48 10HPB60

Mode

C

oil Air

Entering

Temp.
F (C)

liq.

+

10

psig

vap.

+

5

psig

liq.

+

10

psig

vap.

+

5

psig

liq.

+

10

psig

vap.

+

5

psig

liq.

+

10

psig

vap.

+

5

psig

liq.

+

10

psig

vap.

+

5

psig

liq.

+

10

psig

vap.

+

5

psig

liq.

+

10

psig

vap.

+

5

psig

65 (18) 148 71 156 70 165 73 171 68 173 69 163 74 166 71
75 (24) 171 74 182 72 204 70 192 70 205 72 196 74 195 73

Cooli

ng

TXV

85 (29) 200 76 210 74 236 71 222 71 252 73 229 75 227 74

TXV

Only

95 (35) 230 78 241 75 268 73 258 73 278 74 261 77 261 76

y

105 (41) 263 81 275 78 302 74 295 74 315 78 295 78 302 78

20 (−7) 166 33 170 28 178 24 194 26 182 28 178 26 190 27
30 (−1) 177 42 184 36 190 32 208 35 190 36 188 34 204 35

Heating

40 (4) 188 51 194 42 202 39 221 42 202 44 196 42 217 43

50 (10) 200 61 212 56 214 47 236 54 212 54 206 50 234 53

Page 16

Approach Method

4 − Use the same digital thermometer used to check out-

door ambient temperature to check liquid line tempera­ture. Verify the unit charge using the approach method.
The difference between the ambient and liquid temper­atures should match values given in table 7. Add refrig­erant to lower the approach temperature and remove it
to increase the approach temperature. Loss of charge
results in low capacity and efficiency.

5 − If the values don’t agree with the those in table 7, add

refrigerant to lower the approach temperature or re­cover refrigerant from the system to increase the ap­proach temperature.

Table 7

Approach Values

Model

Liquid Temp. Minus Ambient Temp.

_F (_C)

10HPB18 12 (6.7)
10HPB24 13 (7.2)
10HPB30 14 (7.8)
10HPB36 10 (5.6)
10HPB42 13 (7.2)
10HPB48 14 (7.8)
10HPB60 13 (7.2)

NOTE − For best results, the same thermometer should be used to check
both outdoor ambient and liquid temperatures.

IMPORTANT

Use table 6 as a general guide when performing
maintenance checks. This is not a procedure for
charging the unit (Refer to Charging/Checking
Charge section). Minor variations in these pressures
may be expected due to differences in installations.
Significant differences could mean that the system
is not properly charged or that a problem exists with
some component in the system.

System Operation

The outdoor unit and indoor blower cycle on demand from
the room thermostat. When the thermostat blower switch is
in the ON position, the indoor blower operates continuously.

Filter Drier

The unit is equipped with a biflow filter drier. See figure 12.
If replacement is necessary, order another of like design.

Crankcase Heater

IMPORTANT

If unit is equipped with crankcase heater, it should be
energized 24 hours before unit start−up to prevent
compressor damage as a result of slugging.

Emergency Heat Function

An emergency heat function is designed into some room ther­mostats. This feature is applicable when isolation of the out­door unit is required, or when auxiliary electric heat is staged
by outdoor thermostats. When the room thermostat is placed
in the emergency heat position, the outdoor unit control circuit
is isolated from power and field-provided relays bypass the
outdoor thermostats. An amber indicating light simultaneously
comes on to remind the homeowner that he is operating in the
emergency heat mode.

Emergency heat is usually used during an outdoor unit shut
down, but it should also be used following a power outage if
power has been off for over an hour and the outdoor tem­perature is below 50°F (10°C). System should be left in the
emergency heat mode at least six hours to allow the crank­case heater sufficient time to prevent compressor slug­ging.

Defrost System

The 10HPB defrost system includes two components: a
defrost thermostat and a defrost control.

Defrost Thermostat

The defrost thermostat is located on the liquid line between
the check/expansion valve and the distributor. When de­frost thermostat senses 42°F (5.5°C) or cooler, the thermo­stat 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).

Defrost Control

The defrost control board includes the combined func­tions of a time/temperature defrost control, defrost relay,
diagnostic LEDs and terminal strip for field wiring connec­tions. See figure 16.

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

Defrost Control Timing Pins

Each timing pin selection provides a different accumu­lated compressor run time period during one thermostat
run cycle. This time period must occur before a defrost
cycle is initiated. The defrost interval can be adjusted to
30 (T1), 60 (T2), or 90 (T3) minutes. See figure 16. The
defrost timing jumper is factory−installed to provide a
60−minute defrost interval. If the timing selector jumper is
not in place, the control defaults to a 90−minute defrost
interval. The maximum defrost period is 14 minutes and
cannot be adjusted.

A TEST option is provided for troubleshooting. The TEST

mode may be started any time the unit is in the heating

Page 17

mode and the defrost thermostat is closed or jump­ered. If the jumper is in the TEST position at power-up, the

control will ignore the test pins. When the jumper is placed
across the TEST pins for two seconds, the control will enter
the defrost mode. If the jumper is removed before an addi­tional 5−second period has elapsed (7 seconds total), the
unit will remain in defrost mode until the defrost thermostat
opens or 14 minutes have passed. If the jumper is not re­moved until after the additional 5−second period has
elapsed, the defrost will terminate and the test option will
not function again until the jumper is removed and re−ap­plied.

Pressure Switch Circuit

The defrost control incorporates a pressure switch circuit
that allows the application of an optional high pressure
switch. See figure 16. During a demand cycle, the defrost

control will lock out the unit if the optional high pressure
switch opens. The diagnostic LEDs will display a pattern for
an open high pressure switch. See table 8. The unit will re­main locked out until the switch resets or is reset.

Remove the factory-installed jumper before connecting the
optional high pressure switch to the control board.

NOTE − If not using a pressure switch, the factory-installed
jumper wire must be connected.

Diagnostic LEDs

The defrost board uses two LEDs for diagnostics. The LEDs
flash a specific sequence according to the condition.

Table 8

Defrost Control Board Diagnostic LED

Mode LED 1 LED 2

Normal operation /
power to board

Synchronized
Flash with LED 2

Synchronized
Flash with LED 1

Board failure or no power Off Off
Board failure On On
Pressure switch open Flash On

10HPB Defrost Control Board

Figure 16

24V

terminal strip

high pressure switch

connections

S4

connection for

optional

high pressure switch

defrost
interval

timing pins

high

pressure

switch

diagnostic

LEDs

NOTE − Remove factory−installed

jumper to add pressure switch.

Page 18

Maintenance

WARNING

Electric shock hazard. Can cause inju­ry or death. Before attempting to per­form any service or maintenance, turn
the electrical power to unit OFF at dis­connect switch(es). Unit may have
multiple power supplies.

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

Outdoor Unit

1 − Clean and inspect outdoor coil (may be flushed with a

water hose). Make sure power is off before cleaning.

2 − Outdoor unit fan motor is pre-lubricated and sealed. No

further lubrication is needed.

3 − Visually inspect all connecting lines, joints and coils for

evidence of oil leaks.
4 − Check all wiring for loose connections.
5 − Check for correct voltage at unit (unit operating).
6 − Check amp draw on outdoor fan motor.

Unit nameplate__________Actual__________.
7 - Inspect drain holes in coil compartment base and clean

if necessary.

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.

3 − Check condensate line and clean if necessary.

Indoor Unit

1 − Clean or change filters.
2 − 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.

3 − Belt Drive Blowers − Check belt for wear and proper

tension.

4 − Check all wiring for loose connections.
5 − Check for correct voltage at unit. (blower operating)
6 − Check amp draw on blower motor.

Motor nameplate__________Actual__________.

Optional Accessories

Refer to the Engineering Handbook for optional accesso­ries that may apply to this unit. The following may or may
not apply:

 Loss of Charge Kit

 High Pressure Switch Kit
 Compressor Monitor
 Compressor Crankcase Heater

 Hail Guards
 Mounting Bases

 Stand−off Kit

 Sound Cover

 Low Ambient Kit
 Monitor Kit
 Mild Weather Kit

Start−Up and Performance Check List

Start−Up and Performance Check List

Job Name

Job Location
Installer

Unit Model No.
Nameplate Voltage

Rated Load Ampacity
Maximum Fuse or Circuit Breaker

Refrigerant Lines:

Service Valves Fully Opened?

Outdoor Fan Checked?

Job No.

City

City

Serial No.

Date

State

State

Service Technician

Compressor

Outdoor Fan

Indoor Filter Clean?

Electrical Connections Tight?

Supply Voltage (Unit Off)

Vapor Pressure

Thermostat

Refrigerant Charge Checked?

Calibrated? Properly Set?

Level?

Properly Insulated?

Voltage With Compressor Operating

Leak Checked?

Service Valve Caps Tight?

Indoor Blower RPM

Outdoor Coil Entering Air Temp.

Discharge Pressure

S.P. Drop Over Indoor (Dry)