Lennox 12HPB Installation Instructions PDF

1 of 18
1 of 18

Summary of Content for Lennox 12HPB Installation Instructions PDF

Page 1 504,532M

06/04

2002 Lennox Industries Inc.

Dallas, Texas, USA

12HPB Outdoor Units

Lennox Merit Series 12HPB outdoor units are approved

and warranted only for installation with specially

matched indoor coils, line sets, and refrigerant control

devices as designated by Lennox. Refer to Lennox engi-

neering handbook for expansion valve (TXV) kits which

must be ordered separately.

Shipping and Packing List

1 Assembled 12HPB outdoor unit

Check unit for shipping damage. Consult last carrier imme-

diately if damage is found.

WARNING Improper installation, adjustment, alteration, service or maintenance can cause property damage, person- al 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 vent- ing of refrigerant (CFCs and HCFCs) as of July 1, 1992. Approved methods of recovery, recycling or reclaiming must be followed. Fines and/or incarcera- tion may be levied for noncompliance.

INSTALLATION INSTRUCTIONS

12HPB Series Units HEAT PUMP UNITS 2 through 5 tons 504,532M 06/04

Supersedes 04/04

Table of Contents

12HPB 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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . StartUp 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Charging 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . System Operation 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Defrost System 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Maintenance 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Optional Accessories 18. . . . . . . . . . . . . . . . . . . . . . . . . . StartUp 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. Authori-

ties having jurisdiction should be consulted before installa-

tion.

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

Disturbing the insulation during installation, mainte- nance, or repair will expose you to fiberglass wool dust. Breathing this may cause lung cancer. (Fiber- glass 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 753799900

Litho U.S.A.

Page 2

Unit Dimensions inches (mm)

Side View

vapor & liquid line

connections

discharge air

Side View

TOP VIEW

outdoor coil fan

compressor

inlet air

vapor line connection

2-3/4 (70)

A

electrical inlets

liquid line connection

4-3/8 (111)

6-3/8 (162)

6-3/8 (162)

Top View Base Section

4-3/8 (111)

4-3/8 (111)

4-3/8 (111)

4-3/8 (111)

4-3/8 (111)

compressor

coil drain outlets (around perimeter of base)

optional unit stand-off kit (4) (fieldinstalled)

BC

A

optional unit stand-off kit (4) (fieldinstalled)

2 (51)

3/4 (19)

optional unit stand-off kit (4) (fieldinstalled)

inlet air

inlet

air

inlet

air

Model No. A B C

12HPB24 12HPB30 in. 24-1/4 33-1/4 32-1/2

12HPB36 12HPB42 mm 616 819 826

12HPB48 12HPB60 in. 28-1/4 37 36-1/4

mm 718 940 921

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.

Outdoor units operate under a wide range of weather con-

ditions; therefore, several factors must be considered

when positioning the outdoor unit. The unit must be posi-

tioned 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.

36 (914 mm)

Installation Clearances

Figure 1

36* (914 mm)

*NOTE A service clearance of 30" (762 mm) must be main-

tained on one of the sides adjacent to the control box. Clear-

ance 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).

36* (914 mm)

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).

36 (914 mm)

1 Place a sound-absorbing material, such as Isomode,

under the unit if it will be installed in a location or posi-

tion 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 sup-

port 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 the roof mounting section for barrier

construction if the unit must face prevailing winter winds.

Slab Mounting At Ground Level

discharge air

Mounting slab must slope away from building. ground level

structure

Figure 2

Roof Mounting Figure 3

Install the unit a minimum of 6 inches (152 mm) above the

roof surface to avoid ice buildup 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 the barri-

er 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.

wind barrier inlet air

prevailing winter winds

Rooftop Application Wind Barrier ConstrucTion

inlet air

inlet air

inlet air

Figure 3

Electrical

In 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).

Refer to the furnace or blower coil installation instructions

for additional wiring application diagrams and refer to unit

nameplate for minimum circuit ampacity and maximum

overcurrent protection size.

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 low 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

12HPB 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

power power

common common

1st. stage aux. heat 1st. stage aux. heat

indoor blower

compressor

Figure 5

R

C

W1

Y1

O

G

R

C

W1

W2

W3

G

Outdoor Unit and Blower Unit Thermostat Designations

(with emergency 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 em.

heat rly

outdoor tstat

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, non-flare) series line sets as

shown in table 1 or use field-fabricated refrigerant lines.

Refer to Refrigerant Piping Guide (Corp. 9351L9) for prop-

er size, type, and application of fieldfabricated lines. Valve

sizes are also listed in table 1.

Table 1 Refrigerant Line Sets

Valve Size Connections

Recommended Line Set

Model Liquid Line

Vapor Line*

Liquid Line

Vapor Line

L15 Line Sets

24 30

3/8" (9.5 mm)

3/4" (19 mm)

3/8" (9.5 mm)

3/4" (19 mm)

L1541 15 ft. 50 ft.

(4.6 m 15 m)

36 42 48

3/8" (9.5 mm)

7/8" (22.2 mm)

3/8" (9.5 mm)

7/8" (22.2 mm)

L1565 15 ft. 50 ft.

(4.6 m 15 m)

60 3/8"

(9.5 mm) 11/8" (28.5 mm)

3/8" (9.5 mm)

11/8" (28.5 mm)

Field Fabricated

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. 9351L9). 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 highefficiency 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 transmis-

sion.

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

Install unit away from windows .

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

Figure 10

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 sys-

tem.

3 Use silver alloy brazing rods (5 or 6 percent minimum

silver alloy for coppertocopper brazing or 45 percent

silver alloy for coppertobrass or coppertosteel braz-

ing) 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 braz-

ing. 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 fieldprovided thermal expansion valve (ap-

proved for use with HCFC22 refrigerant) in the liquid

line at the indoor coil.

Refrigerant Metering Device

12HPB 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 Chatleff fittings

are available from Lennox. Refer to the Engineering

Handbook for applicable check 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 be-

fore the check expansion valve is installed.

IMPORTANT Failure to remove RFC orifice when installing an ex- pansion valve on the indoor coil will result in improp- er operation and damage to the system.

Table 2

Indoor Check And Expansion Valve Kits

Model Kit Number

12HPB24 12HPB30 12HPB36

LB85759F

12HPB42 12HPB48 12HPB60

LB85759G

See figure 11 for installation of the check expansion valve.

Metering Device Installation

expansion

valve

oring

oring

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 man-

ifold gauge set with anything other than a low loss" hose.

See figure 12 for manifold gauge connections.

Page 11

12HPB Manifold Gauge Connections (Cooling Cycle)

outdoor coil

defrost thermostat

expansion/ check valve

biflow filter / drier

to HCFC22

drum

low pressure

high pressure

compressor

reversing valve

vapor line

valve

muffler

Note Arrows indicate direction of the refrigerant flow.

vapor service

port

expansion/check valve

Indoor Unit

Outdoor Unit

liquid line service

port

GAUGE MANIFOLD

distributor

indoor coil

Figure 12

Service Valves

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

14) and and gauge ports are used for leak testing, evacuat-

ing, charging and checking charge. See table 3 for torque

requirements.

Each valve is equipped with a service port which has a fac-

toryinstalled 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

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 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 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.

Vapor Line (BallType) Service Valve Vapor line service valves function the same way as the oth-

er 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.

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.

Page 12

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

Ball Valve (Valve Open)

Schrader valve

service port

service port cap

stem cap

stem

Use Adjustable Wrench To open: rotate Stem Counter-clockwise 90.

To close: rotate Stem Clockwise 90.

ball (shown open)

to outdoor coil

to indoor coil

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 re- sult 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 equip- ment damage, injury or death. Never use oxygen to pressurize a refrigera- tion 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) pres-

sure.] 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.

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 man-

ifold 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.

Page 13

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 pip-

ing 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 manifold gauge set to the service valve ports :

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 vacuum pump.

5 Evacuate the line set and indoor unit to an absolute

pressure of 23,000 microns (29.01 inches of mercu-

ry). During the early stages of evacuation, it is desir-

able 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 pres-

sure in a vacuum is equal to atmospheric pressure mi-

nus 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 compres- sors 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 20minute 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 vacu-

um 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.

StartUp

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

1 Rotate the 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 to release the refrigerant

charge (contained in outdoor unit) into the system.

4 Replace the stem caps and secure finger tight, then

tighten an additional one-sixth (1/6) of a turn.

5 Check voltage supply at the disconnect switch. The

voltage must be within the range listed on the units

nameplate. If not, do not start the equipment until you

Page 14

have consulted the power company and the voltage

condition has been corrected.

6 Set the thermostat for a cooling demand. Turn on pow-

er to the indoor blower and close the outdoor unit dis-

connect switch 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 re-

frigerant 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.

Table 4

Liquid Line Set Diameter

Oz. per 5 ft. (g per 1.5 m) adjust from 15 ft. (4.6 m) line set*

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 units refrigerant metering device and the

outdoor ambient temperature.

Measure the liquid line temperature and the outdoor ambi-

ent 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 cylin-

der 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 68F

(20C). 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 charg-

ing procedure.

Weighing in the Charge TXV Systems

Outdoor Temp < 65F (18C)

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 re-

paired.

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 proce-

dures outlined below.

Subcooling Method

Outdoor Temp. < 65F (18C)

When the outdoor ambient temperature is below 65F

(18C), use the subcooling method to charge the unit. It

may be necessary to restrict the air flow through the out-

door coil to achieve pressures in the 200250 psig

(13791724 kPa) range. These higher pressures are nec-

essary for checking the charge. Block equal sections of air

intake panels and move obstructions sideways until the liq-

uid pressure is in the 200250 psig (13791724 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 units pressure stabilized, 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 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)

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

subcooling is greater than shown, recover some refrig-

erant. If subcooling is less than shown, add some re-

frigerant.

Table 5 Subcooling Values

Model Subcooling Temp. F (C)

12HPB24 11 (6.1)

12HPB30 5 (2.8)

12HPB36 3 (1.7)

12HPB42 4 (2.2)

12HPB48 4 (2.2)

12HPB60 6 (3.3)

Page 15

Charging Using Normal Operating Pressures

and the Approach Method

Outdoor Temp. > 65F (18C)

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 70F (21C) to 80F (26C).

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 7, 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.

Approach Method

4 Use the same digital thermometer used to check out-

door ambient temperature to check liquid line tempera-

ture. Verify the unit charge using the approach method.

5 The difference between the ambient and liquid temper-

atures should match values given in table 6. If the val-

ues dont agree with the those in table 6, add refriger-

ant to lower the approach temperature or recover re-

frigerant from the system to increase the approach

temperature.

Table 6 Approach Values

Model Liquid Temp. Minus Ambient Temp.

F (C)

12HPB24 6 (3.3)

12HPB30 11 (6.1)

12HPB36 12 (6.7)

12HPB42 10 (5.6)

12HPB48 9 (5)

12HPB60 8 (4.4)

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

Table 7 Normal Operating Pressures

Outdoor Coil 12HPB24 12HPB30 12HPB36 12HPB42 12HPB48 12HPB60

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

65 (183.) 144 78 140 76 152 74 152 75 146 75 146 73

75 (23.9) 170 79 164 77 178 76 179 76 171 77 175 74

85 (29.4) 199 80 194 78 208 77 210 77 198 78 206 75

95 (35) 228 81 224 79 238 78 241 78 229 79 237 76

105 (40.6) 261 82 259 80 275 81 278 79 268 81 275 77

NOTE Typical pressures only. Indoor evaporator match up, indoor air quantity, and evaporator load will cause the pressures to vary.

Page 16

IMPORTANT Use table 7 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 startup to prevent compressor damage as a result of slugging.

Emergency Heat Function (Room Thermostat)

An emergency heat function is designed into some room

thermostats. This feature is applicable when isolation of

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 re-

lays 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 shut-

down, but it should also be used following a power outage if

power has been off for over an hour and the outdoor tem-

perature is below 50F (10C). System should be left in the

emergency heat mode at least six hours to allow the crank-

case heater sufficient time to prevent compressor slug-

ging.

Defrost System

The 12HPB 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 de-

frost thermostat senses 42F (5.5C) or cooler, the thermo-

stat 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 70F (21C).

Defrost Control

The defrost control board includes the combined func-

tions of a time/temperature defrost control, defrost relay,

diagnostic LEDs and terminal strip for field wiring connec-

tions. See figure 16.

The control provides automatic switching from normal

heating operation to defrost mode and back. During com-

pressor cycle (call for defrost), the control accumulates

compressor run times at 30, 60, or 90 minute fieldadjust-

able intervals. If the defrost thermostat is closed when the

selected compressor run time interval ends, the defrost

relay is energized and defrost begins.

Page 17

12HPB Defrost Control Board

24V terminal strip

High Pressure Switch Safety Circuit Connections

S4

connection for optional

high pressure switch

defrost interval

timing pins

high pressure

switch

diagnostic LEDs

Figure 16

NOTE To add pressure switch, remove factory

installed jumper

Defrost Control Timing Pins

Each timing pin selection provides a different accumu-

lated 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 factoryinstalled to provide a

60minute defrost interval. If the timing selector jumper is

not in place, the control defaults to a 90minute 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

mode and the defrost thermostat is closed or jump-

ered. 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 addi-

tional 5second 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 re-

moved until after the additional 5second period has

elapsed, the defrost will terminate and the test option will

not function again until the jumper is removed and reap-

plied.

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 re-

main 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

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 discon- nect 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 or heating season, the system should be checked as fol- lows:

Outdoor Unit

1 Clean and inspect the outdoor coil. The coil may be flushed with a water hose. Ensure the power is turned off before you clean the coil.

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 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 - Lennox blower motors are prelubricated and permanent- ly sealed. No more lubrication is needed.

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.

5 Check all wiring for loose connections.

6 Check for correct voltage at unit. (blower operating)

7 Check amp draw on blower motor. Motor nameplate__________Actual__________.

Optional Accessories

Refer to the Engineering Handbook for optional accesso- ries 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

Standoff Kit

Sound Cover

Low Ambient Kit

Monitor Kit

Mild Weather Kit

StartUp and Performance Check List

Startup 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

Manualsnet FAQs

If you want to find out how the 12HPB Lennox works, you can view and download the Lennox 12HPB Installation Instructions on the Manualsnet website.

Yes, we have the Installation Instructions for Lennox 12HPB as well as other Lennox manuals. All you need to do is to use our search bar and find the user manual that you are looking for.

The Installation Instructions should include all the details that are needed to use a Lennox 12HPB. Full manuals and user guide PDFs can be downloaded from Manualsnet.com.

The best way to navigate the Lennox 12HPB Installation Instructions is by checking the Table of Contents at the top of the page where available. This allows you to navigate a manual by jumping to the section you are looking for.

This Lennox 12HPB Installation Instructions consists of sections like Table of Contents, to name a few. For easier navigation, use the Table of Contents in the upper left corner.

You can download Lennox 12HPB Installation Instructions free of charge simply by clicking the “download” button in the upper right corner of any manuals page. This feature allows you to download any manual in a couple of seconds and is generally in PDF format. You can also save a manual for later by adding it to your saved documents in the user profile.

To be able to print Lennox 12HPB Installation Instructions, simply download the document to your computer. Once downloaded, open the PDF file and print the Lennox 12HPB Installation Instructions as you would any other document. This can usually be achieved by clicking on “File” and then “Print” from the menu bar.