Lennox 15CHAX, 15CHAXA−24, 15CHAXA−30, 15CHAXA−36, 15CHAXA−42 Unit Information

15CHAX

Service Literature

Corp. 0634−L6

15CHAX SERIES UNITS

The 15CHAX packaged heat pump units are available in
sizes ranging from 2 through 5 tons (7.0 through 17.6 kW).
15CHAX units are designed for R−410A refrigerant and out­door residential use only. Units can be installed at ground
level or rooftop applications. Optional field installed supple­mental electric heat is available in 5, 7.5, 10, 15 and 20 kW.

The 15CHAX units utilize a scroll compressor. It operates
much like a standard compressor, but the scroll compressor
is unique in the way that it compresses refrigerant. The
compressor has overload protection.

Information contained in this manual is intended for use by
qualified service technicians only. All specifications are sub­ject to change. Procedures outlined in this manual are pre­sented as a recommendation only and do not supersede or
replace local or state codes.

IMPORTANT

Operating pressures of a R−410A unit are higher
than pressures in R−22 units. Always use service
equipment rated for R−410A.

2 to 5 Ton (7.0 to 17.6 kW)

WARNING

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

ELECTROSTATIC DISCHARGE (ESD)

Precautions and Procedures

CAUTION

Electrostatic discharge can affect electronic
components. Take precautions during unit instal­lation and service to protect the unit’s electronic
controls. Precautions will help to avoid control
exposure to electrostatic discharge by putting
the unit, the control and the technician at the
same electrostatic potential. Neutralize electro­static charge by touching hand and all tools on an
unpainted unit surface before performing any
service procedure.

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.

TABLE of CONTENTS

Specifications / Accessories Page 2. . . . . . . . . .

Electric Heat Capacities Page 3. . . . . . . . . . . . .

Electrical / Electric Heat Data Page 3. . . . . . . .

Parts Arrangement Page 4. . . . . . . . . . . . . . . . .

I Application Page 5. . . . . . . . . . . . . . . . . . . . . . .

II Unit Components Page 5. . . . . . . . . . . . . . . . .

III Electric Heat Page 13. . . . . . . . . . . . . . . . . . . .

IV Charging Page 14. . . . . . . . . . . . . . . . . . . . . . . .

V Maintenance Page 14. . . . . . . . . . . . . . . . . . . . .

VII Wiring Diagrams Page 15. . . . . . . . . . . . . . . .

Page 1

© 2006 Lennox Industries Inc.

Litho U.S.A.

SPECIFICATIONS

g

p

208/240V−1ph

g

g

Power Kits

General
Data

Model No.

Nominal Tonnage 2 2.5 3 3.5 4 5

Cooling
Performance

Total cooling capacity − Btuh 23,000 28,200 35,000 41,500 47,500 59,000

Total unit watts 1850

2

SEER (Btuh/Watt) 14.50 14.00 15.00 14.50 14.00 14.00

EER (Btuh/Watt) 12.40 12.40 12.40 12.40 11.80 11.70

Sound Rating Number (dB) 77 77 77 79 79 79

Refrigerant Type R−410A R−410A R−410A R−410A R−410A R−410A

Refrigerant Charge 7 lbs. 8 oz. 6 lbs. 10 oz. 7 lbs. 13 oz. 11 lbs. 5 oz. 11 lbs. 13 oz. 11 lbs. 12 oz.

Outdoor
Coil

Net face area − sq. ft. (m2) 15.1 15.1 15.1 22 22 22

Tube dia. − in. (mm) & No. of rows 5/16 − 2 5/16 − 2 5/16 − 2 5/16 − 2 5/16 − 2 5/16 − 2

Fins per inch (m) 22 22 22 22 22 22

Indoor
Coil

Tube dia. − in. (mm) & No. of rows 3/8 − 2 3/8 − 2 3/8 − 4 3/8 − 2 3/8 − 3 3/8 − 4

Net face area − sq. ft. (m2) 4.67 4.67 4.67 6 6 6

Fins per inch (m) 14 14 14 14 14 14

Condensate drain size (fpt) − in. 3/4 3/4 3/4 3/4 3/4 3/4
Outdoor

Coil Fan

Indoor
Blower

Diameter − in. & No. of blades 22 − 3 22 − 3 22 − 3 26 − 3 26 − 3 26 − 3

Blower wheel size dia. x width − in. 10 x 6 10 x 6 10 x 8 10 x 10 10 x 10 10 x 10

Motor horsepower 1/5 1/5 1/5 1/4 1/4 1/4

Motor horsepower 1/2 1/2 1/2 3/4 3/4 3/4

Net weight of basic unit 370 370 390 500 510 510
Shipping weight of basic unit (1 Pkg.) 415 415 435 555 565 565
Electrical characteristics (60 hz) 208/230V−1ph−60hz

15CHAXA

−24

15CHAXA

−30

15CHAXA

−36

15CHAXA

−42

15CHAXA

−48

15CHAXA

2275 2820 3350 4030 5040

OPTIONAL ACCESSORIES − MUST BE ORDERED EXTRA

Compressor Crankcase Heater 93M04 S S S S S S
Compressor Hard Start Kit

Compressor Time−Off Control 47J27 S S S S S S
Electric

Heat
Size

−

5 kW − PHK05BP

7.5 kW − PHK07BP
10 kW − PHK10BP
15 kW − PHK15CP
20 kW − PHK20CP

3

Internal Filter Kit

(No.) and size of filters − in.

92M54 − (1) 20 x 25 S S S

92M55 − (2) 16 x 25
Lifting Brackets 92M51 S S S S S S
Low Ambient Kit 34M72 S S S S S S
PCO Accessory Kit 92M53 S S S S S S
Roof Curbs 8 inch height

14 inch height

SignatureStatt Home Comfort Control 81M27 S S S S S S
Single Point

Power Kits

For 5 kW Electric Heat

ASPWR813−01

For 7.5 kW Electric Heat

ASPWR814−01

For 10 kW Electric Heat

ASPWR815−01

For 15−20 kW Electric Heat

ASPWR816−01

NOTE−Extremesofoperatingrangeareplusandminus10%ofline voltage.

1

Annual Fuel Utilization Efficiency based on U.S. DOE test procedures and FTC labeling regulations.

2

Rated in accordance with ARI Standard 210/240; 95_F outdoor air temperature, 80_F db/67_F wb entering evaporator air.

3

Filters are not furnished and must be field provided. 1, 2 or 4 inch thick filters can be used.

4

HACR type circuit breaker or fuse.

5

RefertoNational or CanadianElectricalCodemanualtodeterminewire,fuseanddisconnectsizerequirements.

10J42 S S S S S
81J69 S

10W47 S S S S S S
10W48 S
10W49 S
10W50
10W51

S S S S S
S S S S S

S S S S

S S S

S S S

92M99
93M01
93M00
93M02

S S S

S

S S

S S S

S S S

13W88 S S S S S S

13W89 S

13W90 S

S S S S S

S S S S S

13W91 S S S S

−60

Page 2

ELECTRIC HEAT CAPACITIES

I

p

Protecti

Bl

Motor

A

Bl

Motor

nput

Volta ge

No of
Steps

208 1 3.8 12,800 1 5.6 19,200 1 7.5 17,900 1 11.2 38,200 1 15.0 51,200

220 1 4.2 14,300 1 6.3 21,500 1 8.4 20,100 1 12.6 43,000 1 16.8 57,300

230 1 4.6 15,700 1 6.9 23,500 1 9.2 21,900 1 13.8 47,000 1 18.4 62,700

240 1 5.0 17,100 1 7.5 25,600 1 10.0 23,900 1 15.0 51,200 1 20.0 68,200

5 kW 7.5 kW 10 kW 15 kW 20 kW

kW

input

Btuh

Output

No of
StepskWinput

Btuh

Output

No of
StepskWinput

Btuh

Output

No of
StepskWinput

Btuh

Output

No of

StepskWinput

ELECTRICAL/ELECTRIC HEAT DATA

Model No. 15CHAXA−24 15CHAXA−30 15CHAXA−36 15CHAXA−42 15CHAXA−48 15CHAXA−60

Linevoltagedata − 60hz 1 phase 208/230V 208/230V 208/230V 208/230V 208/230V 208/230V

Compressor

Outdoor Fan
Motor

Indoor
Blower Motor

1

Maximum

Overcurrent

on

Electric

Heat &

Circuit

2

Minimum

Circuit

mpacity

Electric

Heat &

Circuit

NOTE − Circuit 1 Minimum Circuit Ampacity includes the Blower Motor Full Load Amps.
NOTE− Extremesofoperatingrangeareplusandminus10%oflinevoltage.
1 HACR type breaker or fuse.

2

RefertoNational or CanadianElectricalCodemanualtodeterminewire,fuseanddisconnectsizerequirements.

Rated Load Amps 13.4 14.1 14.1 17.9 21.8 26.4

Locked Rotor Amps 58 73 77 112 117 134

Full Load Amps 1.1 1.1 1.1 1.7 1.7 1.7

Locked Rotor Amps 2.2 2.2 2.2 4 4 4

Rated Load Amps 1.5 1.5 1.5 2.7 2.7 2.7

Locked Rotor Amps 3 3 4 5 5 5

Unit only, no electric heat 30 30 30 40 50 60

5 kW 35 35 35 35 35 35

ower

Motor

15 kW

7.5 kW 45 45 45 50 50 50

10 kW 60 60 60 60 60 60

Circuit 1 − − − − − − 60 60 60 60

Circuit 2 − − − − − − 30 30 30 30

20 kW

Circuit 1 − − − − − − − − − 60 60 60

Circuit 2 − − − − − − − − − 60 60 60

Unit only, no electric heat 21 22 22 29 34 39

5 kW 31.3 31.3 31.3 33.0 33.0 33.0

ower

Motor

15 kW

7.5 kW 44.3 44.3 44.3 46.1 46.1 46.1

10 kW 57.3 57.3 57.3 59.1 59.1 59.1

Circuit 1 − − − − − − 57.3 59.1 59.1 59.1

Circuit 2 − − − − − − 26.0 26.0 26.0 26.0

20 kW

Circuit 1 − − − − − − − − − 59.1 59.1 59.1

Circuit 2 − − − − − − − − − 52.1 52.1 52.1

Btuh

Output

Page 3

15CHAX PARTS ARRANGEMENT

TRANSFORMER

(T1)

BLOWER CONTROL

(A54)

FIGURE 1

15CHAX CONTROL BOX

CONTACTOR

SYSTEM OPERATION MONITOR

(A132)

(K1)

DUAL / FAN CAPACITOR

(C12)

FIGURE 2

Page 4

I−APPLICATION

15CHAX 2 through 5 ton (7.0 through 17.6kW) model units
are single phase air conditioning units designed for outdoor
installation on a slab or roof top.The units are available in two
cabinet sizes. Electric heat can be factory or field installed if
required. Refer to the Engineering Handbook for more spe­cific application data.

II−UNIT COMPONENTS

15CHAX components are shown in figure 1. Control box com­ponents are shown in figure 2.

A−Control Box Components

1−Compressor Contactor K1

K1 is a 24VAC to line voltage s ingle pole double break contac­tor, which energizes the compressor in response to thermostat
demand.

2−Control Transformer T1

All 15CHAX series units use line voltage to 24VAC transformer
mounted in the control box. The transformer supplies power to
control circuits in the unit. Transformers use two primary volt­age taps as shown in figure 3.

208 / 240 VOLT TRANSFORMER

PRIMARY

L2

240 VOLTS

208 VOLTS

L1

FIGURE 3

SECONDARY

24 VOLTS

3−Dual Capacitor C12

The compressor and condenser fan in the 15CHAX series
units use permanent split capacitor motors. The capacitor is lo­cated in the control box. A dual rated capacitor is used for both
the condenser fan motor and the compressor (see unit wiring
diagram per respective unit). The fan side and the compressor
side of the capacitor have different MFD ratings. See side of
capacitor for ratings.

4− Blower Control A15

!

WARNING

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

15CHAX units are equipped with a variable speed motor
that is capable of maintaining a specified CFM throughout
the external static range. A particular CFM can be obtained
by positioning jumpers (COOL, HEAT, and ADJUST) on
the blower control board. The HEAT and COOL jumpers
are labeled A, B, C and D. Each of the numbers corre­sponds with an air volume (CFM) setting. The ADJUST
jumper is labeled Test, −, +, and Norm. The + and − pin set­tings are used to add or subtract a percentage of the CFM
selected. The Test jumper is used to operate the motor in
the test mode. See figure 4.

Factory settings for the blower speed jumpers are given in
the wiring diagram. Figure 4 shows the blower control
board. Use tables 1, 2 and 3 to determine the correct air vol­ume for operation in heat and cool mode.

The CFM LED located on the blower control board flashes
one time per 100 cfm to indicate selected blower speed.
For example, if the unit is operating at 1000 CFM, CFM LED
will flash 10 times. If the CFM is 1150, CFM LED will flash 11
full times plus one fast or half flash.

At times the light may appear to flicker or glow. This takes
place when the control is communicating with the motor be­tween cycles. This is normal operation.

Read through the jumper settings section before adjusting
the jumper to obtain the appropriate blower speed.

To change jumper positions, gently pull the jumper off the pins
and place it on the desired set of pins. The following section
outlines the different jumper selections available and condi­tions associated with each one. Refer to figure 4.

After the CFM for each application has been determined,
the jumper settings must be adjusted to reflect those given
in tables 1, 2 and 3. From the tables, determine which row
most closely matches the desired CFM. Once a specific row
has been chosen (+, NORMAL, or −), CFM volumes from
other rows cannot be used. Below are descriptions of the
jumper selections.

The variable speed motor slowly ramps up to and down
from the selected air flow during both cooling and heating
demand. This minimizes noise and eliminates the initial
blast of air when the blower is initially energized.

ADJUST

The ADJUST pins allow the motor to run at normal speed,
approximately 15 percent higher, or approximately 15 per­cent lower than normal speed. Tables 1, 2 and 3 give three
rows (+, NORMAL, and −) with their respective CFM vol­umes. Notice that the normal adjustment setting for cool
speed position D in table 1 is 900 CFM. The + adjustment
setting for that position is 1035 CFM and for the − adjust­ment setting is 765 CFM. After the adjustment setting has
been determined, choose the remaining speed settings
from those offered in the table in that row.

The TEST pin is available to bypass the blower control and
run the motor at approximately 70 percent to make sure that
the motor is operational. This is used mainly in trouble­shooting. The G terminal must be energized for the motor to
run.

Page 5

BLOWER CONTROL BOARD (A54)

16−PIN PLUG

(BOARD TO MOTOR)

ADJUST

SELECTOR PINS
(Setting affects both
heating and cooling

modes)

DIAGNOSTIC

LED

FIGURE 4

COOL

The COOL jumper is used to determine the CFM during
cooling operation. This jumper selection is activated for
cooling when Y1 is energized.

The blower motor runs at 80 percent of the selected air flow
for the first 7−1/2 minutes of each cooling demand. This fea­ture allows for greater humidity removal and saves energy.
In the cooling mode, the blower control board delays blower
operation for 5 seconds after the compressor starts. The
blower continues to operate for 90 seconds after the
compressor is de−energized.

HEAT

The HEAT jumper is used to determine CFM during backup
electric heat operation only. These jumper selections are
activated only when W is energized.
In the backup heat mode, the blower continues to operate
for 2 minutes after the heating demand is satisfied.

NOTE − Due to the nature of electric heat, CFM settings are
limited.

HEATING SPEED
SELECTOR PINS

COOLING SPEED

SELECTOR PINS

CONTINUOUS FAN

When the thermostat is set for Continuous Fan" operation
and there is no demand for heating or cooling, the blower
control will provide 50 percent of the COOL CFM selected.

NOTE − With the proper thermostat and subbase, continu­ous blower operation is possible by closing the R to G cir­cuit. Cooling blower delay is also functional in this mode.

DEHUMIDIFICATION

The blower control board includes an HUM terminal which
provides for connection of a humidistat. The JV1 resistor on
the blower control board must be cut to activate the HUM
terminal. The humidistat must be wired to open on humidity
rise. When the dehumidification circuit is used, the variable
speed motor will reduce the selected air flow rate by 25 per­cent when humidity levels are high. An LED (D1) lights
when the blower is operating in the dehumidification mode.

Page 6

TABLE 1

ADJUST

Jumper

ADJUST

Jumper

JUS

ADJUST

Jumper

15CHAX−24, 15CHAX−30 Blower Performance

0 through 0.80 in. w.g. (0 through 200 Pa) External Static Pressure Range

Jumper Speed Positions



"

Jumper

Setting

NORM 1000 470 800 380 600 285 900 425 1000 470 1000 470 1000 470 1000 470 500 235 400 190 300 140 450 210

A

cfm

1150 545 920 435 690 325 1035 490 1150 545 1150 545 1150 545 1150 545 575 270 460 215 345 165 520 245

+

850 400 680 320 510 240 765 360 1000 470 1000 470 1000 470 1000 470 425 200 340 160 300 140 385 180

−

COOL" Speed

B C D A B C D A B C D

L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s

HEAT" Speed CONTINUOUS FAN" Speed

TABLE 2

15CHAX−36 Blower Performance

0 through 0.80 in. w.g. (0 through 200 Pa) External Static Pressure Range

Jumper Speed Positions



"

Jumper

Setting

NORM 1200 565 1000 470 800 380 1100 520 1200 565 1200 565 1000 470 1000 470 600 285 500 235 400 190 550 260

A

cfm

1380 650 1150 545 920 435 1265 575 1380 650 1380 650 1150 545 1150 545 690 325 575 270 460 215 635 300

+

− 1020 480 850 400 680 320 935 440 1200 565 1200 565 1000 470 1000 470 510 240 425 200 350 165 470 220

COOL" Speed

B C D A B C D A B C D

L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s

HEAT" Speed CONTINUOUS FAN" Speed

TABLE 3

15CHAX−42, 15CHAX−48, 15CHAX−60, Blower Performance

0 through 0.80 in. w.g. (0 through 200 Pa) External Static Pressure Range

Jumper Speed Positions

AD

T"

Jumper

Setting

NORM 1800 850 1600 755 1400 660 1200 565 1400 660 1400 660 1400 660 1400 660 900 425 800 380 700 330 600 285

A

cfm

2070 975 1840 870 1610 760 1380 650 1610 760 1610 760 1610 760 1610 760 1035 490 920 435 805 380 690 325

+

− 1530 720 1360 640 1190 560 1020 480 1400 660 1400 660 1400 660 1400 660 765 360 680 320 595 280 510 240

COOL" Speed

B C D A B C D A B C D

L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s cfm L/s

HEAT" Speed CONTINUOUS FAN" Speed

5−Lennox System Operation Monitor (A132)

IMPORTANT

This monitor does not provide safety protection. The
monitor is a monitoring device only and cannot con­trol or shut down other devices.

The Lennox system operation monitor (LSOM) detects
the most common fault conditions in the air conditioning
system. When an abnormal condition is detected, the
module communicates the specific condition through its
ALERT and TRIP lights. The module is capable of detect­ing both mechanical and electrical system problems. See
figure 5 for the system operation monitor.

Lennox System Operation Monitor (A132)

POWER LED

DATA OUTPUT

Y

C

R

ALERT LED

TRIP LED

DATA OUTPUT
CONNECTOR

.25" SPADE
CONNECTOR (5)

LSOM LED Functions

Power LED (green) −− Voltage within the range of

19−28VAC is present at the system monitor power connec­tion.

Alert LED (yellow) −− Communicates an abnormal sys­tem condition through a unique flash code. The alert LED
flashes a number of times consecutively; then pauses;
then repeats the process. This consecutive flashing cor­responds with a particular abnormal condition.

Trip LED (red) −− Indicates a demand signal from the ther­mostat; but detects no current to the compressor.

Flash code number −− Corresponds to a number of LED
flashes, followed by a pause, and then repeated.

Trip & Alert LEDs flashing simultaneously −− Indicates
that the control circuit voltage is too low for operation.

Reset ALERT flash code by removing 24VAC power from
monitor. Last ALERT flash code will display for 1 minute
after monitor is powered on.

LSOM codes are given in table 4.

Page 7

TABLE 4

System Operation Monitor LED Troubleshooting Codes

Status LED Condition Status LED Description Status LED Troubleshooting Information

Green Power" LED ON Module has power 24VAC control power is present at the module terminal.

Green Power" LED OFF Module not powering up

Red Trip" LED ON System and compressor

check out OK

Thermostat demand signal
Y1 is present, but compres­sor not running

Red Trip" & Yellow
Alert" LEDs Flashing

Yellow Alert" Flash
Code 1*

Simultaneous flashing. Indicates that the control circuit voltage is too low for operation.

Long Run Time −
Compressor is running
extremely long run cycles

Yellow Alert" Flash
Code 2*

System Pressure Trip −

Discharge or suction pres­sure out of limits or
compressor overloaded

Yellow Alert" Flash
Code 3*

Yellow Alert" Flash

Short Cycling − Compres-

sor is running only briefly

Locked Rotor

Code 4*

Yellow Alert" Flash

Open Circuit

Code 5*

Yellow Alert" Flash
Code 6*

Yellow Alert" Flash
Code 7*

Yellow Alert" Flash
Code 8*

Yellow Alert" Flash
Code 9*

Open Start Circuit − Cur-

rent only in run circuit

Open Run Circuit − Current
only in start circuit

Welded Contactor − Com-
pressor always runs

Low Voltage − Control cir­cuit <17VAC

*Flash code number corresponds to a number of LED flashes, followed by a pause, and then repeated. Reset ALERT flash code by
removing 24VAC power from monitor; last code will display for 1 minute after monitor is powered on.

Determine/verify that both R and C module terminals are connected and
voltage is present at both terminals.

1.

2.

3.

Verify Y terminal is connected to 24VAC at contactor coil.
Verify voltage at contactor coil falls below 0.5VAC when off.
Verify 24VAC is present across Y and C when thermostat

demand signal is present; if not present, R and C wires are reversed.

1.

2.

3.

4.

5.

6.

1.

2.

3.

4.

5.

6.

7.

1.

2.

3.

4.

5.

1.

2.

3.

4.

1.

2.

3.

4.

1.

2.

3.

4.

5.

6.

7.

1.

2.

3.

1.

2.

1.

2.

1.

2.

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

Low refrigerant charge.
Evaporator blower is not running.
Evaporator coil is frozen.
Faulty metering device.
Condenser coil is dirty
Liquid line restriction (filter drier blocked if present)
Thermostat is malfunctioning

.

.

.

High head pressure.
Condenser coil poor air circulation (dirty, blocked, damaged).
Condenser fan is not running.
Return air duct has substantial leakage.
If low pressure switch is present, see Flash Code 1 info.

Thermostat demand signal is intermittent.
Time delay relay or control board is defective.
If high pressure switch is present, see Flash Code 2 info.
If low pressure switch is present, see Flash Code 1 info.

Run capacitor has failed.
Low line voltage (contact utility).
Excessive liquid refrigerant in the compressor.
Compressor bearings are seized.

Outdoor unit power disconnect is open.
Unit circuit breaker or fuse(s) is open.
Unit contactor has failed to close.
High pressure switch is open and requires manual reset.
Open circuit in compressor supply wiring or connections.
Unusually long compressor protector reset time due to
extreme ambient temperature.
Compressor windings are damaged.

Run capacitor has failed.
Open circuit in compressor start wiring or connections.
Compressor start winding is damaged.

Open circuit in compressor start wiring or connections.
Compressor start winding is damaged.

Compressor contactor failed to open.
Thermostat demand signal not connected to module.

Control circuit transformer is overloaded.
Low line voltage (contact utility).

Page 8

B−Blower Compartment

Access panels can easily be removed for service.

1−Blower Wheel

Blower wheel size varies between models. See SPECIFI­CATIONS.

2−Variable Speed Motor (B3)

15CHAX units use a three-phase, electronically controlled
D.C. brushless motor (controller converts single phase a.c. to
three phase D.C.), with a permanent-magnet-type rotor (fig­ure 6). Because this motor has a permanent magnet rotor it
does not need brushes like conventional D.C. motors.
Internal components are shown in figure 7. The stator wind­ings are split into three poles which are electrically connected
to the controller. This arrangement allows mo t o r win d i n gs to
turn on and off in sequence by the controller.

A solid-state controller is permanently attached to the
motor. The controller is primarily an A.C. to D.C. convert­er. Converted D.C. power is used to drive the motor. The
controller contains a microprocessor which monitors
varying conditions inside the motor (such as motor work­load).

BLOWER MOTOR B3

J48

SHAFT

tion"). This allows for precise control of motor speed and allows
the motor to compensate for varying load conditions as sensed
by the controller. In this case, the controller monitors the static
workload on the motor and varies motor rpm in order to main­tain constant airflow (cfm).

The motor controller is driven by the blower control
board (figure 4). The board receives its demand (PWM
signal or fixed 24 VAC or VDC signal) from optional controls
such as the Harmony zone control system, Lennox Signatu­reStatt or a conventional thermostat.

Motor rpm is continually adjusted internally to maintain
constant static pressure against the blower wheel. The control­ler monitors the static work load on the motor and motor amp­draw to determine the amount of rpm adjustment. Blower rpm
may be adjusted any amount in order to maintain a constant
cfm as shown in Blower Ratings Tables (1, 2 and 3). The cfm
remains relatively stable over a broad range of static pressure.
Since the blower constantly adjusts rpm to maintain a specified
cfm, motor rpm is not rated. Hence, the terms cool speed" ,
heat speed " or speed tap" if used in this manual, on the unit
wiring diagram and on blower B3, refer to blower cfm regard­less of motor rpm.

When Harmony is used, speed taps are overridden and a
PWM signal generated by the Harmony controller continuously
varies motor speed based upon zone demands.

Initial Power Up

MOTOR

CONTROLLER

J49

FIGURE 6

BLOWER MOTOR COMPONENTS

STATOR

(WINDINGS)

BEARING

OUTPUT

SHAFT

ROTOR

FIGURE 7

The controller uses sensing devices to sense what position
the rotor is in at any given time. By sensing the position of the
rotor and then switching the motor windings on and off in se­quence, the rotor shaft turns the blower.

All blower motors use single phase power. An external
run capacitor is not used. The motor uses permanently
lubricated ball-type bearings.

Internal Operation

Each time the controller switches a stator winding (figure 7) on
and off, it is called a pulse." The length of time each pulse
stays on is called the pulse width." By varying the pulse width ,
the controller varies motor speed (called pulse-width modula-

When line voltage is applied to B3, there will be a large inrush
of power lasting less than 1/4 second. This inrush charges a
bank of DC filter capacitors inside the controller. If the discon­nect switch is bounced when the disconnect is closed, the dis­connect contacts may become welded. Try not to bounce the
disconnect switch when applying power to the unit.

Motor Start-Up

When B3 begins start-up, the motor gently vibrates back and
forth for a moment. This is normal. During this time the elec­tronic controller is determining the exact position of the rotor.
Once the motor begins turning, the controller slowly eases the
motor up to speed (this is called soft-start"). The motor may
take as long as 10-15 seconds to reach full speed. If the motor
does not reach 200rpm within 13 seconds, the motor shuts
down. Then the motor will immediately attempt a restart. The
shutdown feature provides protection in case of a frozen bear­ing or blocked blower wheel. The motor may attempt to start
eight times. If the motor does not start after the eighth try, the
controller locks out. Reset controller by momentarily turning off
power to unit.

The DC filter capacitors inside the controller are connected
electrically to the speed tap wires. The capacitors take
approximately 5 minutes to discharge when the disconnect
is opened. For this reason it is necessary to wait at least 5
minutes after turning off power to the unit before attempt­ing to change speed taps.

Page 9

DANGER

Disconnect power from unit and
wait at least five minutes to allow
capacitors to discharge before at­tempting to adjust motor speed tap
settings. Failure to wait may cause
personal injury or death.

External Operation (Speed Tap Priority)

Figure 8 shows the two quick-connect jacks (J48 and J49)
which connect the motor to the 15CHAX. Jack J48 is the
power plug and jack J49 connects the unit controls to the
motor.

Line voltage must be applied to J48 pin 5 in order for the mo­tor to operate. When using 120VAC pins 1 and 2 must be
jumpered. When control voltage is applied to J49 pin 3 and
15, the motor is energized on the continuous fan mode.

When voltage is applied to J49 pin 2 in addition to pin 3 and
15 (first stage heating), the blower is energized on the low
speed heating tap. When voltage is applied to J49 pin 13 in
addition to pin 3 and 15 (second stage heating), the blower
is energized on the high speed heating tap. The motor as­signs priority to J49 pin 2 so that if a call for cooling and a call for
heating are concurrent, heating call overrides and the blower
operates on high speed heating tap.

Precautions

If the 15CHAX or its electronically controlled blower motor is
improperly or inadequately grounded, it may cause television
interference (commonly known as RFI or radio frequency inter­ference).

This interference is caused by internal switching fre­quencies of the motor controller. TV interference may
show up as small sp e c k s or lin es which randomly appear on
the TV screen accompanied by pops or clicks in the sound. Be­fore attempting any service, make sure the indoor unit is caus­ing the interference. To check, disconnect power to indoor unit
then check TV for continued signs of interference.

TV interference may be stopped by making sure the mo­tor is solidly grounded to the cabinet (metal to metal) and
by making sure the cabinet is solidly grounded. If TV inter­fe rence persi sts, make sure the television (and all affected
RF appliances) are moved away from the 15CHAX. Also make
sure affected appliances are connected to a separate electrical
circuit.

BLOWER B3 HARNESS CONNECTORS

POWER

CONNECTOR J48

J48
PIN 1 - Jumper PIN 1 to PIN2 for 120VAC line input only.
PIN 2 - Jumper PIN 1 to PIN2 for 120VAC line input only.
PIN 3 - Ground
PIN 4 - AC Line
PIN 5 - AC Line

CONTROL

CONNECTOR J49

J49
PIN 1 - C1
PIN 2 - W / W1

11

PIN 3 - C2
PIN 4 − Delay
PIN 5 - Cool
PIN 6 - Y1
PIN 7 - Adjust
PIN 8 - 0ut
PIN 9 - 0
PIN 10 - DS(PWM)
PIN 11 - Heat
PIN 12 - R
PIN 13 - EM / W2
PIN 14 - Y / Y2
PIN 15 - G
PIN 16 - Out +

FIGURE 8

Page 10

Using the transformer in the unit, test motor operation by jumping 24 volts
into the terminals illustrated below for the desired speed.

LOW (continuous blower) SPEED

12345678 910111213

J46

C

R

1. Disconnect power to unit.

2. Disconnect plug J46 from P46 located on the
blower control board.

3. Disconnect C and R from ignition control
board.

4. Disconnect Y" from ignition control and con­nect a separate wire between R" on the
transformer and Y" on the ignition control.

5. Connect voltage source as shown above.

6. Turn on power to unit. Blower should operate
at LOW speed.

COOLING SPEED

12345678 910111213

J46

C

R

7− Disconnect power to unit.
8− Connect voltage source as shown above.
9− Disconnect Y" on ignition control and con-

nect a separate wire between R" on trans­former and Y" on ignition control.

10− Turn on power to unit. Blower should oper-

ate at COOLING speed.

VARIABLE SPEED CHECKOUT

14 15

16

To Y" on ignition control. !

14 15

16

To Y" on ignition control.

J46

C

J46

C

HEATING SPEED

12345678 91011121314 15

R

11− Disconnect power to unit.
12− Connect voltage source as shown above.
13− Disconnect W" from ignition control and

connect a separate wire between R" on
transformer and W" on the ignition control.

14− Turn on power to unit. Blower should operate

at HEATING speed.

16

To W" on on ignition control.

HIGH HEATING SPEED

1 2 3 4 5 6 7 8 9 10111213

R

15− Disconnect power to unit.
16− Connect voltage source as shown above.
17− Disconnect W2" from ignition control and

connect a separate wire between R" on
transformer and W2" on ignition control.

18− Turn on power to unit. Blower should operate

at HIGH HEATING speed.

14 15

To W2" on ignition control.

16

J49 CONTROL CONNECTOR VOLTAGE WHEN VOLTAGE IS PRESENT

PIN 1 C1 Common Low voltage transformer is powered

PIN 2 W / W1 24VAC W1 (1st stage heating) call from thermostat

PIN 3 C2 Common Low voltage transformer is powered

PIN 4 Delay see note

PIN 5 Cool see note

1

1

Low voltage transformer is powered

Low voltage transformer is powered

PIN 6 Y1 24VAC Y (cooling) call from thermostat

PIN 7 Adjust see note

1

Low voltage transformer is powered

PIN 8 Out Motor sends pulse signals between pin 8 and pin 16 to signal CFM

PIN 9 O 24VAC From thermostat (in heat pump application)

PIN 10 DS / PWM 0 / 24 VAC Low voltage is transformer is powered and humidistat operation:

24VAC = normal humidity, 0VAC = high humidity (reduced CFM)

PIN 11 Heat see note

1

Low voltage transformer powered

PIN 12 R 24VAC Low voltage transformer is powered

PIN 13 EM / W2 24VAC W2 (2nd stage heating) call from thermostat

PIN 14 Y / Y2 Not used on single stage cooling

PIN 15 G 24VAC G is present from thermostat

PIN 16 Out Motor sends pulse signals between pin 8 and 16 to signal CFM

1

signal from selection taps − A tap = 0 volts, B and C taps = half wave, D tap = 24VAC

Page 11

C−Cooling Components

SCROLL COMPRESSOR

DISCHARGE

CROSS−SECTION OF SCROLLS

DISCHARGE

PRESSURE

DISCHARGE

STATIONARY

SCROLL

SUCTION

ORBITING

SCROLL

SUCTION

FIGURE 9

The scroll compressor design is simple, efficient and re­quires few moving parts. A cutaway diagram of the scroll
compressor is shown in figure 9. The scrolls are located in
the top of the compressor can and the motor is located in
the bottom of the compressor can. The oil level is immedi­ately below the motor.

The scroll is a simple compression concept centered
around the unique spiral shape of the scroll and its inherent
properties. Two identical scrolls are mated together form­ing concentric spiral shapes (figure 10). One scroll remains
stationary, while the other is allowed to "orbit" (figure 11).
Note that the orbiting scroll does not rotate or turn but mere­ly orbits the stationary scroll.

NOTE − The head of a scroll compressor may be hot since it
is in constant contact with discharge gas.

TIPS SEALED BY

DISCHARGE PRESSURE

FIGURE 10

The counterclockwise orbiting scroll draws gas into the outer
crescent shaped gas pocket created by the two scrolls (fig­ure (figure 11 − 1). The centrifugal action of the orbiting scroll
seals off the flanks of the scrolls (figure 11 − 2). As the orbiting
motion continues, the gas is forced toward the center of the
scroll and the gas pocket becomes compressed (figure 11 −

3). When the compressed gas reaches the center, it is dis­charged vertically into a chamber and discharge port in the
top of the compressor (figure 9). The discharge pressure
forcing down on the top scroll helps seal off the upper and
lower edges (tips) of the scrolls (figure 10). During a single
orbit, several pockets of gas are compressed simultaneously
providing smooth continuous compression.

The scroll compressor is tolerant to the effects of liquid re­turn. If liquid enters the scrolls, the orbiting scroll is allowed
to separate from the stationary scroll. Continued slugging of
liquid will cause damage to the scroll and replacement will
be necessary. The liquid is worked toward the center of the
scroll and is discharged. If the compressor is replaced, con­ventional Lennox cleanup practices must be used.

1

SUCTION

POCKET

SUCTION

3

SUCTION

ORBITING

SCROLL

STATIONARY

SCROLL

HIGH PRESSURE GAS

SUCTION

2

FLANKS SEALED

BY CENTRIFUGAL FORCE

MOVEMENT OF ORBIT

FIGURE 11

INTERMEDIATE PRESSURE

GAS

CRECENT SHAPED

GAS POCKET

SUCTION

4

DISCHARGE

POCKET

Page 12

1−Condenser Fan

All 15CHAX units use single phase condenser fans. Specifica­tions for the condenser fans are at the front of this manual. See
figure 12 for fan and motor replacement.

1 1/2"

fan guard

hub and shaft
should be flush

FIGURE

12

2−High Pressure Switch S4

S4 is a N.C. auto−reset high pressure switch located on the
liquid line. The switch shuts off the compressor when liquid
pressure rises above the factory setting. The switch on
15CHAX units is set to open at 590 + 10 psi and close at
418 + 10 psi.

3−Low Pressure Switch (S79)

2−Heating Element HE1 through HE4

Heating elements are composed of helix−wound bare nich­rome wire exposed directly to the air stream. The elements are
supported by insulators mounted to the wire frame. Each ele­ment is energized independently by a corresponding relay lo­cated on the heat vest panel. Once energized, heat transfer is
instantaneous.

PHK VESTIBULE PARTS ARRANGEMENT

(PHK−10)

TB 2

SEQUENCER

RELAY

PRIMARY

LIMITS

The low pressure switch is an auto−reset N.C. switch that
opens on pressure drop. The switch is wired in series with
the high pressure switch S4 and compressor contactor
K1 and is located on the suction line . When suction pres­sure drops to 10 psig (68.95kPa) the switch opens and the
compressor is de−energized. When suction pressure
rises to 30 psig (206.85 kPa) the pressure switch will
close.

III−Electric Heat
A−Matchups and Ratings

Matchups and ratings are listed with ELECTRICAL DATA"
See table of contents.

B−Electric Heat Components

See figure 13 for electric heat parts arrangement.

1− Limit Switches 1, 2, 3 and 4

Limit switches 1, 2, 3and 4 are N.C. auto−reset high tempera­ture limits located on the electric heat vest panel. Each heating
element is wired in series with a high temperature limit. When
the limit opens the corresponding heating element is de−ener­gized. All other heating elements remain energized. The limits
will automatically close when temperatures return to normal.
Limit rating will be on front side.

FIGURE 13

3−Terminal Strip TB2 PHK−05, −07, −10

For electric heat sections without circuit breakers or fuses, line
voltage connections are made to terminal strip TB2.

4− Sequencer Relays 1 and 2

Relays 1 and 2 are N.O. sequencer relays with a resistive ele­ment for a coil and bi−metal disk which actuates the contacts.
The relays are located on the electric heat vest panel and are
energized by a 24V heating demand (W1 and W2) via jack/
plug P2 which is used to connect electric heat to the blower
control circuit. When energized, the internal resistance heats
the bi−metal disk causing the contacts to close. When the relay
is de−energized the disk cools and the contacts open. The re­lays energize different stages of heat, as well as the blower.
The blower is always first on and last off.

5−Circuit Breaker CB1 and CB2 (option)

PHK−15, −20,

Line voltage connections are made to circuit breakers CB1 and
CB2 in electric heat sections with circuit breakers. Table 5
shows amp rating for each circuit breaker used. Two−pole cir­cuit breakers are used.

TABLE 5

Circuit Breakers

UNIT CB1 AMPS CB2 AMPS
PHK15CP 60 AMPS 30 AMPS
PHK20CP 60 AMPS 60 AMPS

Page 13

IV−Charging

System Performance

For maximum performance of this cooling system, the
operating temperatures and pressure should be checked
and subcooling determined at Standard ARI test conditions
of 82_ F outdoor temperature / 80_ F indoor dry bulb / 67_ F
indoor wet bulb. If subcooling measured deviates from
values in table 6, refrigerant charge should be adjusted
accordingly for maximum performance.

TABLE 6

Subcooling Values

Unit Model No.

82_F OD / 80_F IDDB

/ 67_F IDWB

Verify system performance using table 7 as a general guide.
Table 7 should not be used for charging unit. 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.

Used carefully, this table could serve as a useful service
guide. Data is based on 80°F dry bulb / 67°F wet bulb return
air. Allow unit operation to stabilize before taking pressure
readings.

15CHAX−24
15CHAX−30

15CHAX−36 15_

15CHAX−42
15CHAX−48
15CHAX−60

12_

10_

Table 7

Normal Operating Pressures

80°F db / 67°F wb RETURN AIR Air Temperature Entering Outdoor Coil (°F)

UNIT PRESSURE 65 70 75 80 82 85 90 95 100 105 110 11 5
15CHAX−24 142 143 144 146 146 147 148 149 150 151 152 153
15CHAX−30 134 136 138 140 141 142 144 146 148 149 151 152
15CHAX−36
15CHAX−42
15CHAX−48 140 141 142 144 144 145 146 147 148 149 150 151
15CHAX−60 143 144 145 146 146 147 147 148 149 150 151 152
15CHAX−24 219 242 264 287 296 310 333 355 379 398 430 457
15CHAX−30 232 255 277 300 309 323 345 368 390 408 440 470
15CHAX−36
15CHAX−42
15CHAX−48 243 264 285 307 315 328 349 370 391 408 440 470
15CHAX−60 257 280 303 326 335 349 372 395 418 436 468 497

Suction

Liquid

143 144 146 147 148 149 151 152 155 155 157 157
140 140 140 141 141 141 142 142 143 144 145 147

244 268 292 316 326 340 363 369 410 429 461 493
225 247 269 291 300 314 337 357 383 402 434 457

V−Maintenance

At the start of each cooling season, this equipment should
be serviced by a qualified technician. Periodic inspection
and maintenance normally consists of changing or cleaning
filters.

Filters

Not supplied. Inspect once a month. Replace disposable or
clean permanent type as necessary. DO NOT replace per­manent type with disposable.

Motors

Indoor, outdoor fan and vent motors are permanently
lubricated and require no further lubrication. Motors
should be cleaned yearly to prevent the accumulation of
dust and dirt on the windings or motor exterior.

Coil

Dirt and debris should not be allowed to accumulate on the
coil surfaces or other parts in the air conditioning circuit.
Cleaning should be performed as often as necessary. Use a
brush, vacuum cleaner attachment, or other suitable
means. If water is used to clean the coil, be sure the power
to unit is shut off prior to cleaning.

NOTE − Care should be used when cleaning the coil so that
the coil fins are not damaged.

Do not permit the hot condenser air discharge to be ob­structed by overhanging structures or shrubs.

Page 14

VI−Wiring Diagram and Sequence of Operation

A−Unit Diagram

Page 15

B−PHK Electric Heat

HE3HE3

HE4HE4

ELECTRIC HEAT - 2ND STAGEELECTRIC HEAT - 2ND STAGE

LIMIT SWITCH 3LIMIT SWITCH 3

BLKBLK

BLKBLK

BLKBLK

44

11

SEQUENCER 2SEQUENCER 2

55

33

BLUBLU

Wiring Diagram - Electric HeatWiring Diagram - Electric Heat

BLKBLK

BLKBLK

LIMIT SWITCH 4LIMIT SWITCH 4

YELYEL

HE1HE1

HE2HE2

ELECTRIC HEAT - 1ST STAGEELECTRIC HEAT - 1ST STAGE

LIMIT SWITCH 3LIMIT SWITCH 3

BLKBLK

WHTWHT

44

YELYEL

SEQUENCER 1SEQUENCER 1

55

BLUBLU

BLKBLK

LIMIT SWITCH 4LIMIT SWITCH 4

BLKBLK

11

YELYEL

YELYEL

33

BLKBLK

BLKBLK

WHTWHT

BLUBLU

REDRED

POWER (FACTORY WIRED)POWER (FACTORY WIRED)

6-PIN6-PIN

POWER FIELD WIRED)POWER FIELD WIRED)

66

55

PLUGPLUG

44

33

CONTROL (FACTORY WIRED)CONTROL (FACTORY WIRED)

%%uHEATER ELEMENTS USED:%%uHEATER ELEMENTS USED:

5KW-HE15KW-HE1

7.57.5 & 10KW - HE1& 10KW - HE1 & HE2& HE2

15KW - HE1, HE2,15KW - HE1, HE2, & HE3& HE3

5566

44

33

20KW - HE1, HE2, HE3,20KW - HE1, HE2, HE3, & HE4& HE4

WHTWHT

WHTWHT

BLUBLU

REDRED

6-PIN6-PIN

PLUGPLUG

66

33

22

55

11

44

W2W2

W1W1

TO THERMOSTATTO THERMOSTAT

PACKAGE UNITPACKAGE UNIT

WIRINGWIRING

CIRCUIT BREAKER 2 (OPT)CIRCUIT BREAKER 2 (OPT)

( IF USED )( IF USED )

SINGLE POINTSINGLE POINT

POWER ACCESSORYPOWER ACCESSORY

RELAYRELAY

GNDGND

CIRCUIT BREAKER 1 (OPT)CIRCUIT BREAKER 1 (OPT)

L2L2

L1L1

208/240208/240

VOLTAGEVOLTAGE

BY OTHERSBY OTHERS

L1L1

L2L2

L2L2

L1L1

GNDGND

YELYEL

BLKBLK

CIRCUITCIRCUIT

BREAKERBREAKER

COMPRESSORCOMPRESSOR

1122

BLOWERBLOWER

MOTORMOTOR

BLOWERBLOWER

22

11

YELYEL

BLKBLK

BLKBLK

BLKBLK

24V24V

208V208V

L1L1 L2L2

TO CONTACTORTO CONTACTOR

Page 16