Lennox Merit 14HPX-042 Installation Instructions Manual

Brand: Lennox

Model: Merit 14HPX-042

Category: Split-system air conditioners

Type: Installation Instructions Manual

This manual is also suitable for

,1_2008 Lennox Industries Inc,

Dallas, Texas, USA

INSTALLATION

INSTRUCTIONS

14HPX Series Units

HEAT PUMP UNITS _Technical

505,243M LLJJ Publications

04108 Litho U.S.A.

Supersedes 03/08

RETAIN THESE INSTRUCTIONS

FOR FUTURE REFERENCE

WARNING

CAUTION

14HPX Outdoor Unit ........................... 1

Shipping and Packing List ...................... 1

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

General Information ........................... 3

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

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

Refrigerant Piping ............................. 5

Flushing Existing Line Set and Indoor Coil ........ 8

Refrigerant Metering Device .................... 9

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

Service Valves ................................ 10

Leak Testing .................................. 11

Evacuation ................................... 11

Start-Up ...................................... 12

Refrigerant Charge ............................ 12

Checking Indoor Airflow ....................... 12

Setup for Checking and Adding Charge .......... 13

System Operation ............................. 17

Defrost System ............................... 17

Maintenance .................................. 22

Optional Accessories .......................... 23

Homeowner Information ........................ 23

Thermostat Operation .......................... 24

14HPX Check List ............................. 24

IMPORTANT

14HPX Merit ® outdoor units use HFC-410A refrigerant.

This unit must be installed with a matching indoor blower

coil and line set as outlined in the Lennox Engineering

Handbook. 14HPX outdoor units are designed for use in

expansion valve systems only. They are not designed to be

used with other refrigerant flow control devices. An expan-

sion valve approved for use with HFC-410A must be or-

dered separately and must be installed prior to operating

the unit.

1-Assembled 14HPX outdoor unit

Check the unit components for shipping damage. If you

find any damage, immediately contact the last carrier.

04/08

[[IHHI[III[IIIHIlII[IIIII[[IH[III Page 1 505,243M

[III[I[[IIII[I[[I[I[IIIIIII[IIHI[[III

INLET AIR

,_ INLET AIR

INLET AIR

iT_

4-3/8

(111)

OPTIONAL UNIT STAND-OFF KIT

(4) (FIELD-INSTALLED)

COIL DRAIN OUTLETS ir

(AROUND PERIMETER OF

BASE)

5-3/8

VAPOR LINE CONNECTION (152)

INLET AIR,,_i_ LIQUID LINE CONNECTION "_

TOP VIEW TOP VIEW BASE SECTION

A _--J

,91--- A_' OUTDOOR COIL FAN tD SCHARGE A R

4-3/8

(111)

4-3/8

(111)

COMPRESSOR

VAPOR AND LIQUID

LINE CONNECTIONS

2-3/4 (70)

OPTIONAL UNIT

STAND-OFF KIT (4)

(FIELDqNSTALLED)

SIDE VIEW 3/4(19) _i SIDE VIEW

Model No. ABC

14HPX-018 24-1/4 (616) 29-1/4 (743) 28-1/2 (724)

14HPX-024 24-1/4 (616) 29-1/4 (743) 28-1/2 (724)

14HPX-030 24-1/4 (616) 33-1/4 (845) 32-1/2 (826)

14HPX-036 32-1/4 (819) 29-1/4 (743) 28-1/2 (724)

14HPX-042 32-1/4 (819) 37-1/4 (946) 36-1/2 (927)

14HPX-048 32-1/4 (819) 37-1/4 (946) 36-1/2 (927)

14HPX-060 32-1/4 (819) 43-1/4 (1099) 42-1/4 (1073)

505243 04/08

Page 2

WhenservicingorrepairingHVACcomponents,ensure

capsandfastenersareappropriatelytightened.Table1

liststorquevaluesfortypicalservice/repairitems,

Table1.TorqueRequirements

Part Recommended Torque

Liquid service valve cap 85 in.-lb. 10 NM

Suction service valve cap 85 in.-lb. 10 NM

Sheet metalscrews 16 in.-lb. 2 NM

Machine screws #8 28 in.-lb. 3 NM

Compressor bolts 90 in.-lb. 10 NM

Gauge port seal cap 62 in.-lb. 7 NM

These instructions are intended as a general guide and do

not supersede national or local codes in any way. Consult

authorities having jurisdiction before installation,

WARNING

CAUTION

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, Mount unit high enough above ground or roof to allow

adequate drainage of defrost water and prevent ice

build-up,

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.

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.

(AS NOTED)

*A service clearance of 30" (702 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" (305 mm) and the final side may

be 6" (152 mm).

A clearance of 24" (610 mm) must be maintained between two

units. 48" (1219 mm) clearance required on top of unit+ Maximum

soffit overhang is 36" (914 mm).

Figure 1. Installation Clearances

SLAB MOUNTING

When installing the 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.

The 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 build-up under the unit dur-

ing a defrost cycle. Refer to roof mounting section for barri-

er construction if the unit must face prevailing winter winds,

Unit is shown with optional stand-offs (Cat# 94J35),

DISCHARGE AIR

STRUCTURE 0

OPTIONAL

STAND-OFFS

(CAT#94J35)

MOUNTING SLAB MUST SLOPE GROUND

AWAY FROM BUILDING. LEVEL

Figure 2. Slab Mounting At Ground Level

Page 3

14HPX SERIES

ROOF MOUNTING

Install 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 roof-

top applications

PREVAILING WINTER WINDS

I WINDBARRIER I

INLET AIR

Figure 3. Rooftop Application Wind Barrier

If unit coil cannot be mounted away from prevailing winter

winds, construct a wind barrier Size barrier at least the

same height and width as the outdoor unit Mount barrier

24 inches (610 mm) from the sides of the unit in the direc-

tion of prevailing winds

In the USA. 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)

WARNING I

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

1 Install line voltage power supply to unit from a properly

sized disconnect switch (see figure 6)

2 Ground unit at unit disconnect switch or to an earth

ground (see figure 6)

NOTE -Tofacilitate conduit, a hole is in the bottom of

the control box. Connect conduit to the control box

using 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 6

for field wiring diagram.

NOTE -A complete unit wiring diagram is located in-

side the unit control box cover.

NOTE -For proper voltages, select thermostat wire

gauge per the following chart:

Wire run length AWG # Insulation type

less than 100' (30m) 18 color-coded, temperature

more than 100' (30m) 16 rating 35°C minimum

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.

Install low voltage wiring from outdoor to indoor unit

and from thermostat to indoor unit (see figures 4 & 5).

NOTE -24V, Class II circuit connections are made in

the low voltage junction box.

Thermostat Outdoor Unit

®1 ®

power

common

1st, stage aux heat

indoor blower

reversing valve

Indoor Unit

q_(_ power

_(__ common

iI_ 1st. stage aux. heat

4-@- ,

4®

compressor

(SOME CONNECTIONS MAY NOT APPLY. REFER

TO SPECIFIC THERMOSTAT AND INDOOR UNIT.)

Figure 4. Outdoor Unit/Blower Unit Field Wiring

Indoor UnitThermostat

(R) -- -po-weL - - -_

oommonj

k.C/

(_ emergency h%at __

- _sLst_e Su£_FI l-

indoor btower

reversing valve

compressor

(SOME CONNECTIONS MAY NOT APPLY. REFER TO

SPECIFIC THERMOSTAT AND INDOOR UNIT.)

Outdoor Unit

,_ power (_1

oommon@1

emer

heay_"_/_e_

-®1 ®1

Figure 5. Outdoor Unit/Blower Unit Field Wiring

(with outdoor thermostat and emergency heat relay)

505243 04/08

Page 4

Z_ NOTE-

FOR USE WITH COPPER CONDUCTORS

ONLY.REFER TO UNIT RATIN6

PLATE FOR MINIMUM CIRCUIT

ANPACITY AND MAXIMUM OVER-

CURRENT PROTECTION SIZE

Z_ REFER TO COMPRESSOR IN UNIT

FOR ACTUAL TERMINAL ARRANGEMENT.

/_ WARNING-

ELECTRIC SHOCK HAZARD,CAN CAUSE INJURY

OR DEATH.UNIT MUST BE GREED IN

ACCO_OANCE WITH NATIONAL AND LOCAL CODES.

RTI4 SENSOR, OUTDOOR TEMP (OPTIONAL)

£,87 LOV! LI

PRESSURE REVERSIND

SWITCH VALVE

C_WPBESSO_

CORTACTOR

EQUIPMENT

6ROUND

COMPRESSOR

CONTACTOR

L2_ )--C)

S,€

HI6H

PRESSURE

SWITCH

RTI5

AMBIENT

SENSOR

RT2 I

DEFROST

COIL

SENSOR

CI2

CAPACITOR

O OUT

AI_

DEFROST CONTROL ;OIL

_MB

)IS

OUT

OPS

2 OUT

COMPRESSOR

CONTACTOR

CBSIMV

-'_91_- I-----

--0-1---- --

SIGNATURE

81M2B

TWlSTEO

RTI4

GROUNDz_

208-

mL2 230/

60/_

_GENDTES OPTIONAL COMPONENTS

_LINE VOLTAGE FIELD INSTALLED

-- -- --CLASS II VOLTAGE FIELD INSTALLED

Figure 6. Typical Field Wiring Diagram

Table 2. Refrigerant Line Sets

If the 14HPX unit is being installed with a new indoor coil

and line set, plumbing connections should be made as out-

lined in this section. If an existing line set and/or indoor coil

is going to be used to complete the 14HPX system, refer to

the following section that includes flushing procedures.

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 2 or use field4abricated refrigerant lines.

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

proper size, type, and application of field4abricated lines.

Valve sizes are also listed in table 2.

PLUMBING CONNECTIONS--14HPX MATCHED

WITH NEW INDOOR COIL AND LINE SET

If replacing an existing coil that is equipped with a liquid line

functioning as a metering orifice, replace the liquid line

prior to installing the 14HPX unit. See table 2.

Field

Mod- Connections

el Liquid Vapor

Line Line

-018 3/8in. 3/4in

-024 (10 mm) (19 mm)

-030

-036 3/8 in. 7/8 in

-042 (10 ram) (22 ram)

-048

-060 3/8 in. 1-1/8 in,

(10 mm) (29 mm)

Recommended Line Set

Liquid Vapor L15

Line Line Line Sets

3/8 in. 3/4 in L15-41

(10mm) (19mm) 15 ft. - 50 ft.

(4.6 m - 15 m)

3/8 in, 7/8 in L15-65

(10mm) (22mm) 15 ft, - 50 ft.

(4.6 m- 15 m)

3/8 in. 1-1/8 in, Field

(10 mm) (29 mm) Fabricated

NOTE -Units are designed for line sets of up to fifty feet (15

m); for longer lengths, consult the Lennox Refrigerant Pip-

ing Guide (Corp. 9351-L9). Select line set diameters from

table 2to ensure that oil returns to the compressor.

Page 5

14HPX SERIES

INSTALLING REFRIGERANT LINE

Pay close attention to line set isolation during installation of

any heat pump or a/c system. When properly isolated from

building structures (walls, ceilings, floors), the refrigerant

lines will not create unnecessary vibration and subsequent

noises. Also, consider the following when placing and

installing a high-efficiency outdoor unit:

1, Placement--Some localities are adopting sound ordi-

nances based on the unit's noise level observed from

the adjacent property, not from the installation proper-

ty. Install the unit as far as possible from the property

line. When possible, do not install the unit directly out-

side a window, Glass has a very high level of sound

transmission. Figure 7 shows how to place the outdoor

unit and line set.

2, Line Set Isolation--The following illustrations dem-

onstrate procedures which ensure proper refrigerant

line set isolation, Figure 8 shows how to install line sets

on vertical runs. Figure 9 shows how to make a transi-

tion from horizontal to vertical. Figure 10 shows how

to install line sets on horizontal runs,

Install unit away

from windows.

Two 90° elb_

installed in line set will

• reduce line set vibration.

Figure 7. Unit Placement and Installation

NOTE -Similar instaflation practices should be used it line set Is to be Installed on exterior ot outside wall.

OUTSIDE WALL IMPORTANT - Refrigerant

lines must not contact wall. VAPOR LINE LI UID LINE

IMPORTANT!

Refrigerant

lines must

not contact

structure,

VAPOR LINE WRAPPED

WITH ARMAFLEX LIt?NIED

iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii_!

CAULK

PVC PIPE FIBERGLASS

INSULATION

WIRE TIE

s INSlDEWALL

STRAP

SLEEVE

WIRE TIE

WOOD BLOCK

WIRE TIE

STRAP

SLEEVE

Figure 8. Refrigerant Line Sets: Installing Vertical Runs (new construction shown

505243 04/08

Page 6

ANCHORED

HEAVY NYLON

WIRE TIE

AUTOMOTIVE

MUFFLER-TYPE

HANGER

WALL

STUD WALL

STUD

Strap Liquid

Line To Va- Strap Liquid Line

por Line To Vapor Line

)UID LINE LIQUID LINE

METAL VAPOR LINE - WRAPPED METAL VAPOR LINE - WRAPPED

SLEEVE IN ARMAFLEX SLEEVE IN ARMAFLEX

Figure 9. Refrigerant Line Sets: Transition From Vertical To Horizontal

To hang line set from joist or rafter,

use either metal strapping material

or anchored heavy nylon wire ties. 8 feet

WIRE TIE

(Around vapor line only)

STRAPPING MATERIAL

(Around vapor line only)

feet

METAL FLOOR JOIST OR

SLEEVE ROOF RAFTER

TAPE OR WIRE TIE H

\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.

Figure 10. Refrigerant Line Sets: Installing Horizontal Runs

WARNING

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. Flow dry nitrogen through the refrigerant piping while

making line set connections; this prevents carbon de-

posits (oxidation) buildup on the inside of the joints be-

ing brazed. Such buildup may restrict refrigerant flow

through screens and metering devices. To do this:

• Flow_ulated nitrogen (at 1 to 2 psig) through the

refrigeration gauge set into the Schrader port con-

nection on the vapor service valve and out of the

Schrader port connection on the liquid service

valve. (Metering device [TXV and RFC] will allow

low pressure nitrogen to flow through the system.)

• While nitrogen is flowing, braze refrigerant line set

to the indoor and outdoor units. IMPORTANT: The

flow of nitrogen must have an escape path

other than through the joint to be brazed.

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 HFC-410A refrig-

erant.

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.

Page 7

14HPX SERIES

NOTE -The tube end must stay bottomed in the fitting

during final assembly to ensure proper seating, seal-

ing and rigidity.

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

proved for use with HFC-410A refrigerant) in the liquid

line at the indoor coil,

,A WARNING I

IMPORTANT

• Connect to the existing unit, a clean recovery cyl-

inder and the recovery machine according to the

instructions provided with the recovery machine.

• Remove all HCFC-22 refrigerant from the existing

system. Check gauges after shutdown to confirm

that the entire system is completely void of refrig-

erant.

• Disconnect the liquid and vapor lines from the ex-

isting outdoor unit.

If the existing outdoor unit is equipped with

manual shut-off valves AND you plan to use NEW

HCFC-22 refrigerant to flush the system -

• Start the existing HCFC-22 system in the cooling

mode and close the liquid line valve.

• Pump all of the existing HCFC-22 refrigerant back

into the outdoor unit. (it may be necessary to by-

pass the low pressure switches to ensure com-

plete refrigerant evacuation,)

• When the low side system pressures reach 0 psig,

close the vapor line valve.

• Disconnect all power to the existing outdoor unit.

Check gauges after shutdown to confirm that the

valves are not allowing refrigerant to flow back into

the low side of the system,

• Disconnect the liquid and vapor lines from the ex-

isting outdoor unit.

2, Remove the existing outdoor unit. Set the new

HFC-410A unit and follow the brazing connection pro-

cedure (see page 7) to make line set connections.

DO NOT install metering device at this time.

3, Make low voltage and line voltage connections to the

new outdoor unit. DO NOT turn on power to the unit

or open outdoor unit service valves at this time.

IMPORTANT

CAUTION

REQUIRED EQUIPMENT

You will need the following equipment in order to flush the

existing line set and indoor coil: two clean HCFC-22 recov-

ery bottles, an oilless recovery machine with a pump down

feature, and two sets of gauges (one for use with HCFC-22

and one for use with the HFC-410A),

FLUSHING PROCEDURE

1, Remove existing HCFC-22 refrigerant using the ap-

propriate 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 HCFC-22 refrig-

erant to flush the system -

• Disconnect all power to the existing outdoor unit,

505243 04/08

Page 8

4, Remove the existing refrigerant flow control orifice or

thermal expansion/check valve before continuing with

flushing procedures. The existing devices are not ap-

proved for use with HFC-410A refrigerant and may

prevent proper flushing, Use a field-provided fitting to

reconnect the lines.

5, Remove the pressure tap valve cores from the 14HPX

unit's service valves. Connect an HCFC-22 cylinder

with clean refrigerant to the vapor service valve. Con-

nect the HCFC-22 gauge set to the liquid line valve and

connect a recovery machine with an empty recovery

tank to the gauge set.

6, 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 ex-

isting system line set and indoor coil.

7, Invert the cylinder of clean HCFC-22 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,

Inverted HCFC-22 Cylinder

(Contains clean HCFC-22 to be

used for flushing)

RECOVERY CYLINDER

EXISTING VAPOR LINE VAPOR LINE

SERVICE VALVE

EXISTING LIQUID LINE LIQUID LINE

SERVICE VALVE

Tank ReturnInlet

, Discharge

RECOVERY MACHINE

Low High

Pressure Pressure

NOTE - The inverted HCFC-22 cylinder must

contain at least the same amount of refrigerant

as was recovered from the existing system.

Figure 11. Flushing Connections

8. After all of the liquid refrigerant has been recovered,

switch the recovery machine to vapor recovery so that

all of the HCFC-22 vapor is recovered,

NOTE -A single system flush should remove all of the

mineral oil from the existing refrigerant lines and in-

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 on the system at the end of the

procedure.

9. Close the valve on the inverted HCFC-22 drum and

the gauge set valves. Pump the remaining refrigerant

out of the recovery machine and turn the machine off,

10. Use dry nitrogen to break the vacuum on the refriger-

ant lines and indoor coil before removing the recovery

machine, gauges and HCFC-22 refrigerant drum. Re-

install pressure tap valve cores into 14HPX service

valves.

11. Install the provided check/expansion valve (approved

for use with HFC-410A refrigerant) in the liquid line at

the indoor coil.

14HPX units are used in check expansion valve (CTXV)

systems only. See the Lennox Engineering Handbook for

approved valve match-ups and application information,

NOTE -HFC-410A systems will not operate properly with

an HCFC-22 valve.

Check expansion valves equipped with Chatlefffittingsare

available from Lennox. Refer to the Engineering Hand-

book for applicable check expansion valves for use with

specific match-ups, See table 3 for applicable check ex-

pansion valve kits,

Table 3. Indoor Check Expansion Valve Kits

MODEL Kit Number

14HPX-018, -024, -030 49L24

14HPX-036, -042 49L25

14HPX-048, -060 91M02

Page 9

14HPX SERIES

IMPORTANT

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. See figure 12 for instal-

lation of the check expansion valve,

(Uncased Coil Shown) _.

TWO PIECE |

PATCH PLATE |ORIFICE

(uncased coil ORIFICE IEXPANSI_N VALVE

only) HOUSING I (see note)

TUBES _

ACCESS FITTING

(no valve core)

On smaller suction lines, bulb may be

mounted on top or side-mounled (prefer-

ably at 3 o'clock position).

On 5/8" and larger lines, mount bulb

approximately at the 4 or 8 o'clock posi-

tions; never mount on bottom of line.

9_clock NOTE - If necessary, remove

HCFC-22 flow control device

(fixed orifice/check expansion

valve) from existing line set before

installing HFC-410A approved ex-

pans on va ve and o-r rig,

Figure 12. Metering Device Installation

Manifold gauge sets used with systems charged with

HFC-410A refrigerant must be capable of handling the

higher system operating pressures, The gauges should be

rated for use with pressures d0 - 800 on the high side and

a low side of 30" vacuum to 250 psi with dampened speed

to 500 psi. Gauge hoses must be rated for use at up to 800

psi of pressure with a 4000 psi burst rating,

The service valves (liquid line - figure 13, vapor line - figure

14) and gauge ports are used for leak testing, evacuating,

charging and checking charge, 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.

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 and

tighten finger tight; then tighten per table 1 (on page 3),

TO OPEN FRONT-SEATED SERVICE VALVES:

1. Remove stem cap with an adjustable wrench,

2, Use a service wrench with a hex-head extension

(3/16" for liquid-line valve sizes; 5/16" for vapor-line

valve sizes) toback the stem out counterclockwise as

far as it will go,

3. Replace the stem cap. Tighten finger tight; then tighten

per table 1 (on page 3).

TO CLOSE FRONT-SEATED SERVICE VALVES:

1. Remove the stem cap with an adjustable wrench,

2. Use a service wrench with a hex-head extension

(3/16" for liquid-line valve sizes; 5/16" for vapor-line

valve sizes) to turn the stem clockwise to seat the

valve. Tighten it firmly,

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

per table 1 (on page 3),

Vapor Line Ball Valve

Ball-type service valves (see figure 14) function the same

way as the other valves but cannot be rebuilt; if one fails,

replace with a new valve, The ball valve is equipped with a

service port with a factory-installed Schrader valve. A ser-

vice port cap protects the Schrader valve from contamina-

tion and assures a leak-free seal.

STEM INSERT HEX

SCHRADER CAP

VALVE]OPENTO ;NO°

LINE SET WHEN

VALVE IS CLOSED

(FRONT SEATED)]

OU%

DOOR

COIL

SERVICE

PORT CAP (VALVE FRONT-SEATED)

Valve in closed position Valve in open position

Figure 13. Front-Seated Liquid Line Valve

_ STEM

CAP TO

OUTDOOR

COIL

USE ADJUSTABLE WRENCH STEM

TO OPEN: ROTATE STEM ,_ Tk _-.._,_j2_-'_ \

COUNTER-CLOCKWISE 90 °. _

TO CLOSE: ROTATE STEM

CLOCKWISE 90 °.

BALL (SHOWN

CLOSED)

' SERVICE PORT

SCHRADER VALVE

INDOO

COIL SERVICE

PORT CAP

Figure 14. Bali-Type Vapor Valve (Valve Closed)

505243 04/08

Page 10

Afterthelinesethasbeenconnectedtotheindoorandout-

doorunits,checkthelinesetconnectionsandindoorunit

forleaks.

WARNING

,WARNING

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.

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

HFC-410A mixture, Correct any leaks and recheck,

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

,&,WARNING

USING AN ELECTRONIC LEAK DETECTOR

IMPORTANT

1, Connect a cylinder of HFC-410A to the center port of

the manifold gauge set.

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

the HFC-410A cylinder (vapor only),

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

the HFC-410A into the line set and indoor unit. Weigh

in a trace amount of HFC-410A, [A trace amount is a

maximum of 2 ounces (57 g) or 3 pounds (31 kPa)

pressure,] Close the valve on the HFC-410A cylinder

and the valve on the high pressure side of the manifold

gauge set, Disconnect the HFC-410A cylinder.

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

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

1. Connect 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 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 isa 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 cyl-

inder 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.

Page 11

14HPX SERIES

A, WARNING I

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 vac-

uum pump and connect it to an upright cylinder d

HFC-410A 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 HFC-410A cylinder and

remove the manifold gauge set,

,&,IMPORTANT

1. Check that fan rotates freely.

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

connections.

NOTE -After the system has been evacuated and before

completing aft the remaining start-up steps, this is the ideal

time to adjust the amount of refrigerant made necessary by

line set length difference and by the specific indoor unit

matchup. Skip to the paragraph "Setup for Checking and

Adding Charge" on Page 13 to setup for charging and for

determine if charge is needed; adjust the charge accord-

ingly.

3, Open the liquid line and vapor line service valves

(counterclockwise) to release refrigerant charge (con-

tained in outdoor unit) into the system,

4, Replace stem caps and tighten finger tight; then tighten

per table 1 (on page 3),

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 pow-

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

connect to start the unit,

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

be within range shown on the nameplate,

This system is charged with HFC-410A refrigerant which

operates at much higher pressures than HCFC-22, The

recommended check expansion valve is approved for use

with HFC-410A. Do not replace it with a valve that is de-

signed to be used with HCFC-22. This unit is NOT ap-

proved for use with coils that include metering orifices or

capillary tubes,

The unit is factory-charged with the amount of HFC-410A

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. A blank space is provided on the unit

rating plate to list the actual field charge,

,& IMPORTANT

NOTE -Be sure that filters and indoor and outdoor coils are

clean before testing.

505243 04/08

Page 12

I Wet-bulb °F

24 24 24 23 23 22

23 23 23 22 22 21

22 22 22 21 21 20

21 21 21 20 19 19

20 20 19 18 17 17

19 19 18 18 17 17

57 58 59 60 61 62

I)T

22 22 20 19 18 17 16 15

21 20 19 18 17 16 15 14

19 19 18 17 16 15 14 13

18 17 16 16 15 14 13 12

161L_5._15 14 13 12 11 10

16 15 15 14 13 12 11 10 I

63 64 65 66 67 68 69 70 I

DRY

BULB

INDOOR t WET

COIL BULB

Step 1. Determine the desired l)T--Measure entering air tempera-

ture using dry bulb (A) and wet bulb (B). DT is the intersecting value of

A and B in the table (see triangle).

Step 2. Find temperature drop across coil--Measure the coil's dry

bulb entering and leaving air temperatures (A and C). Temperature

Drop Formula: (TDrop) = A minus C.

Step 3. Determine if fan needs adjustment--If the difference be-

tween the measured TDrop and the desired I)T (TDropiDT) is within

+3°, no adjustment is needed. See examples: Assume DT = 15 and A

temp. = 72°, these C temperatures would necessitate stated actions:

C° TDrop- DT = °F ACTION

53° 19 -15 = 4 Increase the airflow

58° 14 -15 = -1 (within +3 ° range) no change

62°10 - 15 = -5 Decrease the airflow

Step 4. Adjust the fan speed--See indoor unit instructions to in-

crease/decrease fan speed.

Changing air flow affects all temperatures; recheck temperatures to

confirm that the temperature drop and DT are within +30

Figure 15. Checking Indoor Airflow over Evaporator Coil using Delta-T (I)T) Chart

OUTDOOR UNIT

CHECK

EXPANSION VALVE

LOW HUGH

PRESSURE PRESSURE

LIQUID

LINE I

VALVE

DISTRIBUTOR

(_ BIFLO

FILTER /

DRIER OUTDOOR

CO,L

MUFFLER

SERV

:_ COMPRESSOR

NOTE - ARROWS INDICATE DIRECTION

OF REFRIGERANT FLOW

REVERSING VALVE

_ APOR

LINE

VALVE

CHECK EXPANSION 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.

INDOOR_INI

.--'-1

--,ll_l I I

INDOOR

COIL

Figure 16. 14HPX Cooling Cycle (Showing Gauge Manifold Connections)

COOLING MODE INDOOR AIRFLOW CHECK

Check airflow using the Delta-T (DT) process (figure 15).

HEATING MODE INDOOR AIRFLOW CHECK

Blower airflow (CFM) may be calculated by energizing

electric heat and measuring:

• temperature rise between the return air and supply air

temperatures at the indoor coil blower unit,

• measuring voltage supplied to the unit,

• measuring amperage being drawn by the heat unit(s).

Then, apply the measurements taken in following formula

to determine CFM:

Amps x Voltsx 3.41

CFM = 1.08x Temperature rise (F)

SETUP FOR CHARGING

Connect the manifold gauge set to the unit's service ports

(see figure 16):

• low pressure gauge to vapor service port

• high pressure gauge to liquid service port

Close manifold gauge set valves. Connect the center man-

ifold hose to an upright cylinder of HFC-410A.

CALCULATING CHARGE

If the system is void of refrigerant, first, locate and repair

any leaks and then weigh in the refrigerant charge into the

unit. To calculate the total refrigerant charge:

Amount Adjust amt. for Additional charge

specified variation in specified per

on line set length indoor unit matchup Total

nameplate (table in figure 17) (tables 4 through 10) charge

+ + =

Page13

14HPX SERIES

WEIGH

RefrigerantCharge per LineSet Length

Liquid Line Ounces per 5 feet (g per 1.5m)

Set Diameter adjust from 15feet (4.6 m) lineset*

3t8" (9.5 mm) 3 ounce per 5' (85 g per 1.5 m)

NOTE - *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.

LENNOX

DALLAS, EXAS

M/N TSAO31N_4N41G

_3/N pp'A_MHNNNN

i x

IIIIIIIIllllllllllllllllllll

1. Check Liquid and suction line pressures

2. Compare unit pressures with table 12,

Normal Operating Pressures.

3. Conduct leak check; evacuate as

previously outlined.

4. Weigh in the unit nameplate charge plus

any charge required for line set differences

over feet,

This nameplate isfor illustration purposes

only. Go to actual nameplate on outdoor

unit for charge information.

Figure 17. Using Weigh In Method

SUBCOOUNG 1

!i !i!ili!i!i iB ii iii 'xiiiiiii_iii_!!iiiiiiii ¸ !i!i¸

iX_ N _

?}i

USE COOLING

MODE

-- 60OF {15 °) --

USE HEATING

MODE

SATo

LIQo -

SCo =

Check the airflow as illustrated in figure 15 to be sure the indoor airflow is as

required. (Make any air flow adjustments before continuing with the following

procedure,)

Measure outdoor ambient temperature; determine whether to use cooling mode

or heating mode to check charge,

Connect gauge set,

Check Liquid and Vapor line pressures, Compare pressures with Normal

Operating Pressures table 11, (The reference table is a general guide. Expect

minor pressure variations. Significant differences may mean improper charge or

other system problem.)

Set thermostat for heat/cool demand, depending on mode being used:

Using cooling mode--When the outdoor ambient temperature is 60°F (15°C) and

above. Target subcooling values in table below are based on 70 to 80°F (21-27°C)

indoor return air temperature; if necessary, operate heating to reach that

temperature range; then set thermostat to cooling mode setpoint to 68°F (20°C).

When pressures have stabilized, continue with step 6,

Using heating mode--When the outdoor ambient temperature is below 60°F (15°C).

Target subcooling values in table below are based on 65-75°F (18-24°C) indoor

return air temperature; if necessary, operate cooling to reach that temperature range;

then set thermostat to heating mode setpoint to 77°F (25°C), When pressures have

stabilized, continue with step 6.

6 Read the liquid line temperature; record in the LIQ° space.

7 Read the liquid line pressure; then find its corresponding temperature in the

temperature/pressure chart listed in table 12 and record it in the SAT° space,

8 Subtract LIQ° temp. from SAT° temp. to determine subcooling; record it in SC°space.

9 Compare SC° results with table below, being sure to note any additional charge for

line set and/or match-up,

10 If subcooling value is greater than shown in tables 4 through 10 for the applicable unit,

remove refrigerant; if less than shown, add refrigerant.

11 If refrigerant is added or removed, repeat steps 6 through 10 to verify charge.

Figure 18. Using Subcooling Method

505243 04/08

Page 14

Table 4.14HPX-018

Target *Add

Subcooling charge

INDOOR MATCHUPS Heat Cool

(+5OF) (±1OF) Ib_oz

CBX27UH-818/824 13 7 8 8

CBX32MV-818/824 15 7 8 8

Table 5.14HPX-024

Target *Add

Subcooling charge

INDOOR MATCHUPS Heat Cool

(+5°F) (+1 °F) Ib oz

CH23-41 16 8 0 2

CBX26UH-824 25 7 8 8

CBX27UH-818/824 15 8 1 2

CBX32M-818/824 16 8 8 14

CBX32M-838 15 8 1 3

CBX32MV-818/824 16 8 8 4

CBX32MV-824/838 15 8 1 2

CH33-42B 14 11 1 18

CH33-36A 16 8 1 8

CH33-36C 16 8 8 4

CR33-38/36AJB/C 25 7 8 2

CX34-25AJB 16 8 8 14

CX34-31AJB 15 8 1 3

CX34-36AJB/C 16 8 1 8

CX34-38AJB S/N# 6007 and after 11 11 2 2

CX34-38AJB before S/N# 6007 14 11 2 2

Table 6.14HPX-030 Target *Add

Subcooling charge

INDOOR MATCHUPS Heat Cool

(±5°F) (_I°F)

CH23-41 11 6 0 8

CH23-51 6 6 1 12

CBX26UH-824 38 8 8 6

CBX26UH-838 29 8 2 3

CBX27UH-030 11 6 2 4

CBX32M-030 11 6 1 6

CBX32M-836 11 6 2 4

CBX32MV-824/838 11 6 1 6

CBX32MV-836 11 6 2 4

C33-44C 11 6 2 3

CH33-36C 11 3 8 8

CH33-42B 6 6 1 12

CR33-38/36AJB/C 38 8 8 8

CX34-31AJB 11 6 1 6

CX34-38AJB S/N# 6007 and after 6 6 2 3

CX34-38AJB before S/N# 8007 11 6 2 3

CX34-43B/C 15 11 2 14

Table 7.14HPX-036

Target *Add

Subcooling charge

INDOOR MATCHUPS Heat Cool

(±5OF) (±1OF) Ib_oz

CBX26UH-836 26 5 0 0

CBX26UH-837 25 4 1 9

CBX27UH-836 13 6 8 3

CBX32M-836 13 6 8 2

CBX32M-842 13 6 8 3

CBX32MV-836 13 6 8 3

CBX32MV-848 11 8 2 5

C33-44C 13 6 8 8

CH33-58/68C 11 8 2 5

CH33-44B 13 6 1 7

CH33-48B 13 6 1 8

Target *Add

Subcooling charge

INDOOR MATCHUPS Heat Cool

(±5OF) (±1OF) Ib oz

iEl==l=_iEoZ_{=lLo_J_il=t=1=_.1

CR33-88/68C 25 4 1 15

CR33-48B/C 25 5 8 9

CX34-49C 13 6 2 4

CX34-43B/C, -58/68C 13 6 1 8

CX34-38AJB S/N# 8007 and after 6 6 8 8

CX34-38AJB before S/N# 6007 13 6 8 8

Table 8. 14HPX-042 Target *Add

Subcooling charge

INDOOR MATCHUPS Heat Cool

(±5OF) (±1OF) Ib_oz

CH23-68 28 9 0 13

CBX26UH-842 27 6 8 8

CBX27UH-842 12 6 8 8

CBX32M-848 12 6 8 7

CBX32MV-848 12 6 8 8

CH33-43 12 6 8 7

CH33-62D 12 6 8 18

CH33-58/68C 12 6 8 7

CH33-68D 12 6 8 4

CR33-58/68C,-68D 26 6 8 4

CX34-62C, -62D 12 6 8 9

CX34-49C 12 6 8 7

CX34-68D 12 6 8 4

Table 9. 14HPX-048

Target *Add

Subcooling charge

INDOOR MATCHUPS Heat Cool

(±5OF) (+1OF) Ib_oz

CH23-68 20 9 2 9

CBX26UH-848 8 7 1 9

CBX27UH-848 11 8 1 2

CBX32M-84& -868 11 8 1 2

CBX32MV-848, -868 11 8 1 2

CBX32MV-868 18 7 1 12

CH33-58/68C 11 8 1 1

CH33-62D 18 7 1 14

CH33-68D 11 8 8 8

CR33-58/68C 35 5 8 8

CR33-68D 37 6 8 8

CX34-62C, -62D 18 7 1 7

CX34-49D 11 8 8 14

CX34-68D 11 8 8 8

Table 10. 14HPX-060

Target *Add

Subcooling charge

INDOOR MATCHUPS Heat Cool

(±5OF) (+1OF) Ib_oz

CH23-68 12 5 0 0

CBX26UH-848 12 7 1 8

CBX26UH-868 14 4 8 8

CBX27UH-868 12 5 8 8

CBX32M-848, -868 12 5 8 8

CBX32MV-848, -868 12 5 8 8

CBX32MV-868 12 7 1 8

CH33-58/68C 12 5 8 8

CH33-62D 12 5 8 8

CX34-62C, -62D 12 7 1 8

NO TE-*Add charge =Extra matchup amount required in addition to charge

indicated on Heat Pump nameplate (remember to also add any charge re-

quired for lineset differences from 15 feet).

Page15

14HPX SERIES

Table 11. Normal Operating Pressures - Liquid +10 & Vapor +5 PSIG*

IMPORTANT

14HPX-018 14HPX-024 14HPX-030 14HPX-036 14HPX-042 14HPX-048 14HPX-060

°F(°C)** Liquid /Vapor Liquid /Vapor Liquid /Vapor Liquid/ Vapor Liquid /Vapor Liquid /Vapor Liquid /Vapor

Cooling

65 (18) 226 /140 233 /137 238 /138 220 /138 223 /125 231 /136 243 /136

70 (21) 244 /141 252 /138 263 /139 236 /140 241 /130 248 /139 263 /137

75 (24) 263 1142 271 I140 279 1139 256 1141 261 I134 271 I140 282 1138

80 (27) 283 /143 292 /141 299 /140 276 /142 282 /138 291 /142 306 /139

85 (29) 302 /144 314 /142 324 /141 298 /143 302 /139 312 /143 327 /140

90 (32) 328 /145 338 /143 340 /142 321 /144 326 /140 335 /144 351 /141

95 (35) 351 /146 361 /145 375 /145 344 /144 349 /141 359 /145 376 /142

100 (38) 376 /147 387 /146 397 /145 369 /146 374 /142 384 /146 401 /143

105 (41) 402 /148 412 /147 424 /147 394 /147 399 /143 411 /148 426 /145

110 (38) 430 /149 441 /148 454 /150 421 /148 428 /145 439 /149 452 /146

115 (45) 465 /150 471 /151 485 /150 449 /149 455 /146 468 /150 484 /148

Heating

60 (15) 346/139 352/138 338/137 350/134 373/139 355/130 351 /117

50 (10) 323/117 331 /114 334/ 112 331 /117 363/ 117 336/ 113 333/105

40 (4) 306 /98 304 /99 312 /93 313 /97 348 /97 315 /88 316 /88

30 (-1) 278 /84 299 /80 302 /74 298 /83 336 /74 296 /72 308 /70

20 (-7) 273 /66 283 /66 280 /53 284 /66 322 /64 286 /64 300 /61

*IMPORTANT--These are most-popular-match-up pressures. Indoor match up and indoor load cause

pressures to vary.

**Temperature of the air entering the outside coil (outdoor ambient temperature).

505243 04/08

Page 16

Table 12. HFC-410A Temp. (°F) - Pressure (Psig)

°F Psig °F Psig °F Psig °F Psig

-40 10.1 21 80.5 56 158.2 91 278.2

-35 13.5 22 82.3 57 161.0 92 282.3

-30 17.2 23 84.1 58 163.9 93 286.5

-25 21.4 24 85.9 59 166.7 94 290.8

-20 25.9 25 87.8 60 169.6 95 295.1

-18 27.8 26 89.7 61 172.6 96 299.4

-16 29.7 27 91.6 62 175.4 97 303.8

-14 31.8 28 93.5 63 178.5 98 308.2

-12 33.9 29 95.5 64 181.6 99 312.7

-10 36.1 30 97.5 65 184.3 100 317.2

-8 38.4 31 99.5 66 187.7 101 321.8

-6 40.7 32 100.8 67 190.9 102 326.4

-4 43.1 33 102.9 68 194.1 103 331.0

-2 45.6 34 105.0 69 197.3 104 335.7

0 48.2 35 107.1 70 200.6 105 340.5

1 49.5 36 109.2 71 203.9 106 345.3

2 50.9 37 111.4 72 207.2 107 350.1

3 52.2 38 113.6 73 210.6 108 355.0

4 53.6 39 115.8 74 214.0 109 360.0

5 55.0 40 118.0 75 217.4 110 365.0

6 56.4 41 120.3 76 220.9 111 370.0

7 57.9 42 122.6 77 224.4 112 375.1

8 59.3 43 125.0 78 228.0 113 380.2

9 60.8 44 127.3 79 231.6 114 385.4

10 62.3 45 129.7 80 235.3 115 390.7

11 63.9 46 132.2 81 239.0 116 396.0

12 65.4 47 134.6 82 242.7 117 401.3

13 67.0 48 137.1 83 246.5 118 406.7

14 68.6 49 139.6 84 250.3 119 412.2

15 70.2 50 142.2 85 254.1 120 417.7

16 71.9 51 144.8 86 258.0 121 423.2

17 73.5 52 147.4 87 262.0 122 428.8

18 75.2 53 150.1 88 266.0 123 434.5

19 77.0 54 152.8 89 270.0 124 440.2

20 78.7 55 155.5 90 274.1 125 445.9

The outdoor unit and indoor blower cycle on demand from

the room thermostat. If the thermostat blower switch is in

the ON position, the indoor blower operates continuously.

FILTER DRIER

The unit is equipped with a large-capacity biflow filter drier

which keeps the system clean and dry. If replacement is

necessary, order another of the same design and capacity.

The replacement filter drier must be suitable for use with

HFC-410A refrigerant.

LOW PRESSURE SWITCH (OPTIONAL)

The 14HPX may be equipped with an optional auto-reset

low pressure switch which is located on the vapor line. The

switch shuts off the compressor when the vapor pressure

falls below the factory setting. This switch, which is ignored

during defrost operation, closes at pressures at or above

55 psig and opens at 25 psig. It is not adjustable.

HIGH PRESSURE SWITCH

The 14HPX is equipped with an auto-reset high pressure

switch (single-pole, single-throw) which is located on the

liquid line. The switch shuts off the compressor when dis-

charge pressure rises above the factory setting. The

switch is normally closed and is permanently adjusted to

trip (open) at 590 + 10 psig (4412 + 69 kPa).

NOTE -A Schrader core is under the pressure switches.

DEFROST SYSTEM DESCRIPTION

The demand defrost controller measures differential tem-

peratures to detect when the system is performing poorly

because of ice build-up on the outdoor coil. The controller

"self-calibrates" when the defrost system starts and after

each system defrost cycle. The defrost control board com-

ponents are shown in figure 19.

The control monitors ambient temperature, outdoor coil

temperature, and total run time to determine when a de-

frost cycle is required. The coil temperature probe is de-

signed with a spring clip to allow mounting to the outside

coil tubing. The location of the coil sensor is important for

proper defrost operation.

NOTE -The demand defrost board accurately measures

the performance of the system as frost accumulates on the

outdoor coil. This typically will translate into longer running

time between defrost cycles as more frost accumulates on

the outdoor coil before the board initiates defrost cycles.

DIAGNOSTIC LEDS

The state (Off, On, Flashing) of two LEDs on the defrost

board (DS1 [Red] and DS2 [Green])indicate diagnostics

conditions that are described in table 14.

TEST PINS --

DEFROST

TERMINATION

PIN SETTINGS

SENSOR

PLUG IN

(COIL & AM-

BIENT

SENSORS)

DELAY

PINS

REVERSING

VALVE

r[-_r- PI

O ®

oo,7= o

0 wI

L0-PS

/Z =

f2 0u_

0 Iololol°l°lol°lol 0

TS_PS Or c _{ 0 _1 Yz

-- LOW

AMBIENT

THERMOSTAT

PINS

-- DIAGNOSTIC

LEDS

t 24V TERMINAL

STRIP

CONNECTIONS

Note - Compo-

nent Locations

Vary by Board

Manufacturer,

Figure 19. Defrost Control Board

DEFROST BOARD PRESSURE SWITCH CONNEC-

TIONS

The unit's automatic reset pressure switches (LOPS - S87

and HI PS - S4) are factory-wired into the defrost board on

the LO-PS and HI-PS terminals, respectively.

Page 17

14HPX SERIES

(OPTIONAL) Low Pressure Switch (LO-PS)--When the

low pressure switch trips, the defrost board will cycle off the

compressor, and the strike counter in the board will count

one strike. The low pressure switch is ignored under the

following conditions:

• during the defrost cycle and 90 seconds after the ter-

mination of defrost

• when the average ambient sensor temperature is be-

low 15° F (-9°C)

• for 90 seconds following the start up of the compressor

• during "test" mode

High Pressure Switch (HI-PS)--When the high pressure

switch trips, the defrost board will cycle off the compressor,

and the strike counter in the board will count one strike.

DEFROST BOARD PRESSURE SWITCH SETTINGS

High Pressure (auto reset) - trip at 590 psig; reset at 418.

Low Pressure (auto reset) - trip at 25 psig; reset at 55.

5-STRIKE LOCKOUT FEATURE

The internal control logic of the board counts the pressure

switch trips only while the Y1 (input) line is active, if a pres-

sure switch opens and closes four times during a Y1 (In-

put), the control logic will reset the pressure switch trip

counter to zero at the end of the Y1 (input). If the pressure

switch opens for a fifth time during the current Y1 (input),

the control will enter a lockout condition.

The 5-strike pressure switch lockout condition can be reset

by cycling OFF the 24-volt power to the control board or by

shorting the TEST pins between 1 and 2 seconds. All timer

functions (run times) will also be reset.

If a pressure switch opens while the Y1 Out line is en-

gaged, a 5-minute short cycle will occur after the switch

closes.

DEFROST SYSTEM SENSORS

Sensors connect to the defrost board through a field-re-

placeable harness assembly that plugs into the board.

Through the sensors, the board detects outdoor ambient,

coil, and discharge temperature fault conditions. As the

detected temperature changes, the resistance across the

sensor changes. Figure 20 shows how the resistance var-

ies as the temperature changes for both type of sensors.

Sensor resistance values can be checked by ohming

across pins shown in table 13.

Table 13. Sensor Tem 3./Resistance Range

Temperature Resistance values Pins/Wire

Sensor Range °F (°C) range (ohms) Color

Outdoor -35 (-37) to 120 280,000 to 3750 3 & 4

(Ambient) (48) (Black)

Coil -35 (-37) to 120 280,000 to 3750 5 & 6

(48) (Brown)

Discharge (if 24 (-4) to 350 41,000 to 103 1 & 2 (Yel-

applicable) (176) low)

Note: Sensor resistance decreases as sensed temperature increases

(see figure 20).

NOTE -When checking the ohms across a sensor, be

aware that a sensor showing a resistance value that is not

within the range shown in table 13, maybe performing as

designed. However, if a shorted or open circuit is detected,

then the sensor may be faulty and the sensor harness will

needs to be replaced.

Coil Sensor--The coil temperature sensor (shown in fig-

ure 21) considers outdoor temperatures below -35°F

(-37°C) or above 120°F (48°C) as a fault. If the coil temper-

ature sensor is detected as being open, shorted or out of

the temperature range of the sensor, the board will not per-

form demand or time/temperature defrost operation and

will display the appropriate fault code. Heating and cooling

operation will be allowed in this fault condition.

Ambient and Coil Sensor

m 7450

11775

_m 15425

l_am_ 19975

26200

m34375

m46275

I62700 85300

I I !

10000 30000 50000 70000 90000

RESISTANCE (OHMS)

Figure 20. Temperature/Resistance Chart

505243 04/08

Page 18

° <::::

COIL SENSORLOCATION

Figure 21. Sensor Locations

Ambient Sensor--The ambient sensor (shown in figure

21) considers outdoor temperatures below -35°F (-37°C)

or above 120°F (48°C) as a fault. If the ambient sensor is

detected as being open, shorted or out of the temperature

range of the sensor, the board will not perform demand de-

frost operation. The board will revert to time/temperature

defrost operation and will display the appropriate fault

code. Heating and cooling operation will be allowed in this

fault condition.

NOTE -Within a single room thermostat demand, if

5-strikes occur, the board will lockout the unit. Defrost

board 24 volt power "R" must be cycled "OFF" or the

"TEST" pins on board must be shorted between 1 to 2 sec-

onds to reset the board.

Defrost Temperature Termination Shunt (Jumper)

Pins--The defrost board selections are: 50, 70, 90, and

100°F (10, 21, 32 and 38°C). The shunt termination pin is

factory set at 50°F (10°C). If the temperature shunt is not

installed, the default termination temperature is 90°F

(32°C).

DELAY MODE

The defrost board has a field-selectable function to reduce

occasional sounds that may occur while the unit is cycling

in and out of the defrost mode. When a jumper is installed

on the DELAY pins, the compressor will be cycled off for 30

seconds going in and out of the defrost mode. Units are

shipped with jumper installed on DELAY pins.

NOTE - The 30 second off cycle is NOTfunctional when

jumpering the TEST pins.

Page 19

14HPX SERIES

OPERATIONAL DESCRIPTION

The defrost control board has three basic operational

modes: normal, calibration, and defrost.

Normal Mode--The demand defrost board monitors the

O line, to determine the system operating mode (heat/

cool), outdoor ambient temperature, coil temperature (out-

door coil) and compressor run time to determine when a

defrost cycle is required.

Calibration Mode--The board is considered uncalibrated

when power is applied to the board, after cool mode opera-

tion, or if the coil temperature exceeds the termination tem-

perature when it is in heat mode,

Calibration of the board occurs after a defrost cycle to en-

sure that there is no ice on the coil, During calibration, the

temperature of both the coil and the ambient sensor are

measured to establish the temperature differential which is

required to allow a defrost cycle,

Defrost Mode--The following paragraphs provide a de-

tailed description of the defrost system operation.

DETAILED DEFROST SYSTEM OPERATION

Defrost Cycles--The demand defrost control board initi-

ates a defrost cycle based on either frost detection or time.

• Frost Detection--If the compressor runs longer than

34 minutes and the actual difference between the clear

coil and frosted coil temperatures exceeds the maxi-

mum difference allowed by the control, a defrost cycle

will be initiated.

IMPORTANT - The demand defrost control board will

allow a greater accumulation of frost and will initiate

fewer defrost cycles than a time/temperature defrost

system.

• Time--If 6 hours of heating mode compressor run

time has elapsed since the last defrost cycle while the

coil temperature remains below 35°F (2°C), the de-

mand defrost control will initiate a defrost cycle.

Actuation--When the reversing valve is de-energized,

the Y1 circuit is energized, and the coil temperature is be-

low 35°F (2°C), the board logs the compressor run time. If

the board is not calibrated, a defrost cycle will be initiated

after 34 minutes of heating mode compressor run time.

The control will attempt to self-calibrate after this (and all

other) defrost cycle(s).

Calibration success depends on stable system tempera-

tures during the 20-minute calibration period. If the board

fails to calibrate, another defrost cycle will be initiated after

90 minutes of heating mode compressor run time. Once

the defrost board is calibrated, it initiates a demand defrost

cycle when the difference between the clear coil and

frosted coil temperatures exceeds the maximum differ-

ence allowed by the control OR after 6 hours of heating

mode compressor run time has been logged since the last

defrost cycle.

NOTE -If ambient or coil fault is detected, the board will not

execute the "TEST" mode.

Termination--The defrost cycle ends when the coil tem-

perature exceeds the termination temperature or after 14

minutes of defrost operation. If the defrost is terminated by

the 14-minute timer, another defrost cycle will be initiated

after 34 minutes of run time.

Test Mode--When Y1 is energized and 24V power is be-

ing applied to the board, a test cycle can be initiated by

placing the termination temperature jumper across the

"Test" pins for 2 to 5 seconds. If the jumper remains across

the "Test" pins longer than 5 seconds, the control will ig-

nore the test pins and revert to normal operation. The

jumper will initiate one cycle per test.

Enter the "TEST" mode by placing a shunt (jumper) across

the "TEST" pins on the board after power-up. (The "TEST"

pins are ignored and the test function is locked out if the

shunt is applied on the "TEST" pins before power-up).

Board timings are reduced, the low-pressure switch is ig-

nored and the board will clear any active lockout condition.

Each test pin shorting will result in one test event. For

each "TEST" the shunt (jumper) must be removed for at

least 1 second and reapplied. Refer to flow chart (figure 22)

for "TEST" operation.

Note: The Y1 input must be active (ON) and the "0" room

thermostat terminal into board must be inactive.

DEFROST BOARD DIAGNOSTICS

See table 14 to determine defrost board operational condi-

tions and to diagnose cause and solution to problems.

505243 04/08

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Lennox Merit 14HPX-042 Installation Instructions Manual

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Model: Merit 14HPX-042

Category: Split-system air conditioners

Type: Installation Instructions Manual

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