Lennox 13ACX−018, 13ACX−024, 13ACX−030, 13ACX−036, 13ACX−042 Unit Information

Corp. 0612−L2

Service Literature

Revised 06−2007

13ACX SERIES UNITS

The 13ACX is a high efficiency residential split−system con­densing unit, which features a scroll compressor and de­signed for R−410A refrigerant. 13ACX units are available in
sizes ranging from 1−1/2 through 5 tons. The series is de­signed for use with an expansion valve in the indoor unit.
This manual is divided into sections which discuss the major
components, refrigerant system, charging procedure, main­tenance and operation sequence.
Information contained in this manual is intended for use by
qualified service technicians only. All specifications are sub­ject to change.

IMPORTANT

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

13ACX

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.

WARNING

Warranty will be voided if covered equipment is re­moved from original installation site. Warranty will
not cover damage or defect resulting from:
Flood, wind, lightning, or installation and operation in
a corrosive atmosphere (chlorine, fluorine, salt, re­cycled waste water, urine, fertilizers, or other damag­ing chemicals).

TABLE OF CONTENTS

General Page 1. . . . . . . . . . . . . . . . . . . . . . . . . . .

Specifications / Electrical Data Page 2. . . . . . . .

I Application Page 3. . . . . . . . . . . . . . . . . . . . . . . .

II Unit Components Page 3. . . . . . . . . . . . . . . . . .

III Refrigeration System Page 6. . . . . . . . . . . . . .

IV Charging Page 7. . . . . . . . . . . . . . . . . . . . . . . .

VI Maintenance Page 13. . . . . . . . . . . . . . . . . . . . .

VII Wiring and Sequence of Operation Page 14.

Page 1

©2006 Lennox Industries Inc.

SPECIFICATIONS

p
p

p

g

General

Model No. 13ACX−018

Data

Nominal Tonnage (kW) 1.5 (5.3) 2 (7.0) 2.5 (8.8) 3 (10.6) 3.5 (12.3) 4 (14.1) 5 (17.6)

Connections
(sweat)

1

Refrigerant (R-410A) furnished 4 lbs. 7 oz.

Liquid line o.d. − in. (mm) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5)

Suction line o.d. − in. (mm) 3/4 (19.1)

(2.01 kg)

Outdoor
Coil - sq. ft. (m2)

Net face area

Outer coil 13.22 (1.23) 15.11 (1.40) 13.22 (1.23) 13.22 (1.23) 15.11 (1.40) 16.33 (1.52) 21.0 (1.95)

Inner coil − − − − − − 12.60 (1.17) 12.60 (1.17) 14.40 (1.34) 15.71 (1.46) 20.25 (1.88)

Tube diameter − in. (mm) 5/16 (8) 5/16 (8) 5/16 (8) 5/16 (8) 5/16 (8) 5/16 (8) 5/16 (8)

Number of rows 1 1 2 2 2 2 2

Fins per inch (m) 22 (866) 22 (866) 22 (866) 22 (866) 22 (866) 22 (866) 22 (866)

Outdoor
Fan

Diameter − in. (mm) 18 (457) 18 (457) 18 (457) 18 (457) 18 (457) 22 (559) 22 (559)

Number of blades 3 3 4 4 4 4 4

Motor hp (W) 1/5 (149) 1/5 (149) 1/5 (149) 1/5 (149) 1/3 (249) 1/4 (186) 1/4 (186)

Cfm (L/s) 2500 (1180) 2500 (1180) 2450 (1155) 2450 (1155) 2930 (1385) 3830 (1805) 3830 (1805)

Rpm 1100 1100 1100 1100 1100 825 825

Watts 200 200 200 200 310 330 330

Shipping Data − lbs. (kg) 1 package 122 (55) 129 (59) 150 (68) 150 (68) 177 (80) 201 (91) 222 (100)

13ACX−024 13ACX−030 13ACX−036 13ACX−042 13ACX−048 13ACX−060

−2 units

3/4 (19.1) 3/4 (19.1) 7/8 (22.2) 7/8 (22.2) 7/8 (22.2) 1-1/8 (28.6)

4 lbs. 14 oz.

(2.21 kg)

6 lbs. 3 oz.

(2.81 kg)

6 lbs. 7 oz.

(2.92 kg)

8 lbs. 14 oz.

(4.03 kg)

8 lbs. 4 oz.

(3.74 kg)

**10 lbs. 0

oz. (4.54 kg)

ELECTRICAL DATA

Line voltage data − 60 hz − 1ph 208/230V 208/230V 208/230V 208/230V 208/230V 208/230V 208/230V

2

Maximum overcurrent protection (amps) 20 30 30 35 40 50 60

3

Minimum circuit ampacity 12.3 17.9 18.7 21.9 24.1 28.9 34.5

Compressor

Rated load amps 9.0 13.4 14.1 16.6 17.9 21.8 26.2

Power factor .96 .97 .98 .98 .94 .95 .98

Locked rotor amps 48 58 73 79 11 2 117 134

Condenser
Fan Motor

Full load amps 1.0 1.0 1.0 1.0 1.9 1.7 1.7

Locked rotor amps 1.9 1.9 1.9 1.9 4.1 3.1 3.1

OPTIONAL ACcESSORIES − must be ordered extra

Compressor Crankcase
Heater

Compressor Hard Start Kit

Compressor Low Ambient Cut−Off 45F08       
Compressor Sound Cover 69J03       
Compressor Time−Off Control 47J27       
Freezestat

3/8 in. tubing 93G35       
1/2 in. tubing 39H29       
5/8 in. tubing 50A93       

Hail Guards

Loss of Charge Kit 84M23       
Low Ambient Kit 34M72       
Mounting Base

Refrigerant
Line Sets

L15−41−20, L15−41−30,

L15−41−40, L15−41−50

L15−65−30, L15−65−40,

Field Fabricate 

Time Delay Relay Kit 58M81       
Unit Stand−Off Kit 94J45       

** Charge for −1 units 11 lbs 2 oz NOTE  Extremes of operating range are plus 10% and minus 5% of line voltage.

2

HACR type circuit breaker or fuse.

3

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

93M05    

31J20

  Factory

10J42 

88M91      

92M88   
92M89  
45M56 
92M94 

69J06     
69J07  

  

  

L15−65−50

1

Refrigerant charge sufficient for 15 ft. (4.6 m) length of refrigerant lines.

Page 2

I − APPLICATION

13ACX condensing units are available in 1−1/2, 2, 2 -1/2, 3,
3 -1/2, 4 and 5 ton capacities. All major components (indoor
blower and coil) must be matched according to Lennox rec­ommendations for the compressor to be covered under war­ranty. Refer to the Engineering Handbook for approved sys­tem matchups.

II − UNIT COMPONENTS

Unit components are illustrated in figure 1.

13ACX PARTS ARRANGEMENT

COMPRESSOR

CONTACTOR

(K1)

GROUNDING

LUG

CONTROL BOX

DUAL CAPACITOR

(C12)

TIMED OFF

CONTROL.

(OPTION)

OUTDOOR FAN

COMPRESSOR

CAPACITOR

TIMED

OFF

CONTROL

(OPTION)

CONTACTOR

FIGURE 1

A − Control Box (Figure 2)

13ACX units are not equipped with a 24V transformer. All
24 VAC controls are powered by the indoor unit. Refer to
wiring diagram.

Electrical openings are provided under the control box cov­er. Field thermostat wiring is made to color-coded pigtail
connections.

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.

FIGURE 2

1 − Compressor Contactor K1

DANGER

Shock Hazard
Remove all power at disconnect

before removing access panel.
Single phase 13ACX units use
single-pole contactors. Potential
exists for electrical shock resulting
in injury or death.
Line voltage exists at all compo­nents (even when unit is not in op­eration).

The compressor is energized by a single−pole contactor lo­cated in the control box. See figure 2. K1 is energized by the
indoor thermostat terminal Y1 (24V) when thermostat de­mand is present.

2 − Dual Capacitor C12

The compressor and fan in 13ACX series units use per­manent split capacitor motors. The capacitor is located
inside the unit control box (see figure 2). A single dual"
capacitor (C12) is used for both the fan motor and the
compressor (see unit wiring diagram). The fan side and
the compressor side of the capacitor have different MFD
ratings. See side of capacitor for ratings.

3 − Timed Off Control TOC (option)

The time delay is electrically connected between thermostat
terminal Y and the compressor contactor. Between cycles,
the compressor contactor is delayed for 5 minutes ± 2 min-
utes but may last as long as 8 minutes. At the end of the
delay, the compressor is allowed to energize. When thermo­stat demand is satisfied, the time delay opens the circuit to
the compressor contactor coil and the compressor is de−en­ergized.

Page 3

B − Compressor

The scroll compressor design is simple, efficient and requires
few moving parts. A cutaway diagram of the scroll compressor
is shown in figure 3. The scrolls are located in the top of the
compressor can and the motor is located just below. The oil lev­el is immediately below the motor.

SCROLL COMPRESSOR

DISCHARGE

SUCTION

FIGURE 3

The scroll is a simple compression concept centered around
the unique spiral shape of the scroll and its inherent properties.
Figure 4 shows the basic scroll form. Two identical scrolls are
mated together forming concentric spiral shapes (figure 5). One
scroll remains stationary, while the other is allowed to "orbit" (fig­ure 6). Note that the orbiting scroll does not rotate or turn but
merely orbits the stationary scroll.

The counterclockwise orbiting scroll draws gas into the outer
crescent shaped gas pocket created by the two scrolls (figure 6

− 1). The centrifugal action of the orbiting scroll seals off the
flanks of the scrolls (figure 6 − 2). As the orbiting motion contin­ues, the gas is forced toward the center of the scroll and the gas
pocket becomes compressed (figure 6 − 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

5). The discharge pressure forcing down on the top scroll helps
seal off the upper and lower edges (tips) of the scrolls (figure 5).
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. 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.

Due to its efficiency, the scroll compressor is capable of draw­ing a much deeper vacuum than reciprocating compressor s .
Deep vacuum operation can cause internal fusite arcing
resulting in damaged internal parts and will result in com­pressor failure. Never use a scroll compressor for eva­cuating or pumping−down" the system. This type of dam­age can be detected and will result in denial of warranty
claims.

The scroll compressor is quieter than a reciprocating com­pressor, however, the two compressors have much different
sound characteristics. The sounds made by a scroll compres­sor do not affect system reliability, performance, or indicate
damage.

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

SCROLL FORM

FIGURE 4

CROSS−SECTION OF SCROLLS

DISCHARGE

DISCHARGE
PRESSURE

TIPS SEALED BY
DISCHARGE PRESSURE

STATIONARY SCROLL

SUCTION

ORBITING SCROLL

FIGURE 5

Page 4

SUCTION

1

SUCTION

POCKET

SUCTION

ORBITING SCROLL

STATIONARY SCROLL

FLANKS SEALED

BY CENTRIFUGAL

MOVEMENT OF ORBIT

SUCTION

FORCE

INTERMEDIATE PRESSURE

GAS

2

CRESCENT

SHAPED

GAS POCKET

SUCTION

3

HIGH PRESSURE GAS

FIGURE 6

C − Condenser Fan Motor

All units use single−phase PSC fan motors which require a run
capacitor. In all units, the condenser fan is controlled by
the compressor contactor.

ELECTRICAL DATA tables in this manual show specifi­cations for condenser fans used in 13ACX ’s.

Access to the condenser fan motor on all units is gained
by removing the four screws securing the fan assembly.
Se e figur e 7. The gr ill fan assembly can be re moved fr o m
the cabinet as one piece. See figure 8. The condenser fan
motor is removed from the fan guard by removing the four
nuts found on top of the grill. See figure 8 if condenser fan
motor replacement is necessary.

DANGER

Make sure all power is disconnected before beginning
electrical service procedures.

Remove

screws

4

ALIGN FAN HUB FLUSH WITH END OF SHAFT

FIGURE 8

DISCHARGE

POCKET

D − Loss of Charge Switch (option)

An auto-reset, single-pole/single-throw low loss of charge
switch is located in the suction line. This switch shuts off the
compressor when suction pressure drops below the factory
setting. The switch is closed during normal operating pres­sure conditions and is permanently adjusted to trip (open) at
25 + 5 psi. The switch automatically resets when suction line
pressure rises above 55 + 5 psi.

E − High Pressure Switch

13ACX units are equipped with a high pressure switch that
is located in the liquid line. The switch (SPST, manual reset,
normally closed) removes power from the compressor con­tactor control circuit when discharge pressure rises above
factory setting at 590 + 10 psi.

Remove

screws

FIGURE 7

Page 5

III − REFRIGERANT SYSTEM

A − Plumbing

Field refrigerant piping consists of liquid and suction lines
from the condensing unit (sweat connections) to the indoor
evaporator coil (sweat connections). Use Lennox L15
(sweat) series line sets as shown in table 1.

TABLE 1

Unit

Liquid

Line

Suction

Line

L15 Line Sets

to outdoor coil

service

port cap

Service Valve

(Valve Closed)

stem cap

service

port

insert hex

wrench here

−018

−024

−030

−036

−042

−048

−060

3/8 in.

(10 mm)

3/8 in.

(10 mm)

3/8 in.

(10 mm)

3/4 in.

(19 mm)

7/8 in.

(22 mm)

1−1/8 in.

(29 mm)

L15−41

15 ft. − 50 ft.

(4.6 m − 15 m)

L15−65

15 ft. − 50 ft.

(4.6 m − 15 m)

Field

Fabricated

The liquid line and vapor line service valves (figures 9 and

10) and gauge ports are accessible from the outside of the
unit. Use the service ports 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. Service valves are not rebuildable. If a valve

has failed, you must replace it.

To Access Schrader Port:

1 − Remove service port cap with an adjustable wrench.
2 − Connect gauge to the service port.
3 − When testing is complete, replace service port cap. Tight-

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

To Open Service Valve:

1 − Remove the stem cap with an adjustable wrench.
2 − Using the adjustable wrench to keep the valve station-

ary, use a service wrench with a hex−head extension to
back the stem out counterclockwise as far as it will go.

NOTE − Use a 3/16" hex head extension for 3/8" line
sizes or a 5/16" extension for large line sizes.

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

an additional 1/6 turn.

To Close Service Valve:

1 − Remove the stem cap with an adjustable wrench.
2 − Using the adjustable wrench to keep the valve station-

ary, use a service wrench with a hex−head extension to
turn the stem clockwise to seat the valve. Tighten the
stem firmly.

NOTE − Use a 3/16" hex head extension for 3/8" line
sizes or a 5/16" extension for large line sizes.

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

additional 1/6 turn.

NOTE − Stem cap must be replaced to help prevent
valve leakage.

Schrader valve open

to line set when valve is

closed (front seated)

(valve front seated)

to indoor coil

Service Valve

insert hex

wrench here

to outdoor coil

service port

cap

(Valve Open)

service

port

to indoor coil

Schrader

valve

FIGURE 9

stem cap

Vapor Line Ball Valve – 5 Ton Units Only

Vapor line service valves function the same way as the other
valves, the difference is in the construction. A ball valve is
illustrated in figure 10.

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

Ball Valve (Valve Open)

Use Adjustable Wrench

To open: rotate Stem Clockwise 90°.

To close: rotate Stem Counter-clockwise 90°.

to outdoor coil

service port

cap

service port

Schrader valve

FIGURE 10

stem cap

stem

ball

(shown open)

to indoor coil

Page 6

IV − CHARGING

WARNING

R−410A refrigerant can be harmful if it is inhaled.
R−410A refrigerant must be used and recovered re­sponsibly.

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

A − Leak Testing

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

IMPORTANT

The Clean Air Act of 1990 bans the intentional venting
of (CFC’s and HFC’s) as of July 1, 1992. Approved
methods of recovery, recycling or reclaiming must be
followed. Fines and/or incarceration my be levied for
noncompliance.

WARNING

Fire, Explosion and Personal Safety
Hazard.
Failure to follow this warning could
result in damage, personal injury or
death.
Never use oxygen to pressurize or
purge refrigeration lines. Oxygen,
when exposed to a spark or open
flame, can cause damage by fire
and / or an explosion, that can re­sult in personal injury or death.

WARNING

Danger of explosion!
When using a high pressure gas such

as dry nitrogen to pressurize a refriger­ant or air conditioning system, use a
regulator that can control the pressure
down to 1 or 2 psig (6.9 to 13.8 kPa).

Using an Electronic Leak Detector

1 − Connect a cylinder of R−410A to the center port of the

manifold gauge set. Connect manifold gauge to service
valve port.

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

R−410A cylinder.

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

R−410A into the line set and indoor unit. Weigh in a trace
amount of R−410A. [A trace amount is a maximum of 2
ounces (57 g) or 3 pounds (31 kPa) pressure.] Close the
valve on the R−410A cylinder and the valve on the high
pressure side of the manifold gauge set. Disconnect the
R−410A cylinder.

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

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

5 − Connect the manifold gauge set high pressure hose to

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

sure hose is connected to the liquid line port; however,
connecting it to the vapor port better protects the man­ifold gauge set from high pressure damage.)

6 − Adjust the nitrogen pressure to 150 psig (1034 kPa).

Open the valve on the high side of the manifold gauge
set which will pressurize line set and indoor unit.

7 − After a few minutes, open a refrigerant port to ensure

the refrigerant you added is adequate to be detected.
(Amounts of refrigerant will vary with line lengths.)
Check all joints for leaks. Purge nitrogen and R−410A
mixture. Correct any leaks and recheck.

B − Evacuating

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

NOTE − This evacuation process is adequate for a new
installation with clean and dry lines. If excessive mois­ture is present, the evacuation process may be required
more than once.

IMPORTANT

Use a thermocouple or thermistor electronic vacuum
gauge that is calibrated in microns. Use an instrument
that reads from 50 microns to at least 20,000 microns.

1 − Connect manifold gauge set to the service valve ports :

 low pressure gauge to vapor line service valve
 high pressure gauge to liquid line service valve

2 − Connect micron gauge.
3 − Connect the vacuum pump (with vacuum gauge) to the

center port of the manifold gauge set.

4 − Open both manifold valves and start the vacuum

pump.

Page 7

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

pressure of 23,000 microns (29.01 inches of mercury).
During the early stages of evacuation, it is desirable to
close the manifold gauge valve at least once to deter­mine if there is a rapid rise in absolute pressure. A rap-
id rise in pressure indicates a relatively large leak. If this
occurs, repeat the leak testing procedure.

NOTE − The term absolute pressure means the total
actual pressure within a given volume or system, above
the absolute zero of pressure. Absolute pressure in a
vacuum is equal to atmospheric pressure minus vacu­um pressure.

6 − When the absolute pressure reaches 23,000 microns

(29.01 inches of mercury), close the manifold gauge
valves, turn off the vacuum pump and disconnect the
manifold gauge center port hose from vacuum pump.
Attach the manifold center port hose to a nitrogen cylin­der with pressure regulator set to 150 psig (1034 kPa)
and purge the air from the hose with nitrogen. Open the
manifold gauge valves to break the vacuum in the line
set and indoor unit. Close the manifold gauge valves.

CAUTION

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

7 − Shut off the nitrogen cylinder and remove the manifold

gauge hose from the cylinder. Open the manifold gauge
valves to release the nitrogen from the line set and in­door unit.

8 − Reconnect the manifold gauge to the vacuum pump,

turn the pump on, and continue to evacuate the line set
and indoor unit until the absolute pressure does not rise
above 500 microns (29.9 inches of mercury) within a
20−minute period after shutting off the vacuum pump
and closing the manifold gauge valves.

9 − When the absolute pressure requirement above has

been met, disconnect the manifold hose from the vacu­um pump and connect it to an upright cylinder of R−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 R−410A cylinder and remove the manifold gauge
set.

C − Charging

This system is charged with R−410A refrigerant which oper­ates at much higher pressures than HCFC−22. The recom­mended check expansion valve is approved for use with
R−410A. Do not replace it with a valve that is designed to be
used with HCFC−22. This unit is NOT approved for use with
coils that include metering orifices or capillary tubes.

Check Indoor Airflow before Charging

NOTE − Be sure that filters and indoor and outdoor coils are clean before testing.

Check indoor airflow using the step procedures as illustrated in figure 11.

Temp.
of air
entering
indoor
coil ºF

A

Wet−bulb ºF

53º

BULB

80 24 24 24 23 23 22 22 22 20 19 18 17 16 15
78 23 23 23 22 22 21 21 20 19 18 17 16 15 14
76 22 22 22 21 21 20 19 19 18 17 16 15 14 13
74 21 21 21 20 19 19 18 17 16 16 15 14 13 12

Dry−bulb

72 20 20 19 18 17 17 16 15 15 14 13 12 11 10

70 19 19 18 18 17 17 16 15 15 14 13 12 11 10

57 58 59 60 61 62 63 64 65 66 67 68 69 70

T

C

Drop

19º

All temperatures are
expressed in ºF

DT

air flowair flow

INDOOR
COIL

Step 1. Determine the desired DT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: (T

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

B

A

72º

B

64º

WET

BULB

DRY BULBDRY

tween the measured T
+3º, no adjustment is needed. See examples: Assume DT = 15 and
A temp. = 72º, these C temperatures would necessitate stated ac­tions:

Cº T

Drop

53º 19 – 15 = 4 Increase the airflow
58º 14 – 15 = −1 (within +3º range) no change
62º 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 +3º.

Drop

– DT = ºF ACTION

FIGURE 11

) = A minus C.

and the desired DT (T

Drop

–DT) is within

Drop

Page 8

Pre−Charge Maintenance Checks1.

TABLE 2

Normal Operating Pressures (TXV)

Use this table to perform maintenance checks; it is not a procedure for charging

IMPORTANT

13ACX

5F (5C)*

Expansion Valve (TXV)

65 (18) 244 / 135 249 / 137 241 / 134 253 / 134 250 / 135 240 / 130 247 / 129 242 / 130
70 (21) 262 / 136 268 / 138 259 / 135 274 / 135 268 / 137 257 / 131 265 / 130 266 / 131
75 (24) 281 / 137 288 / 138 279 / 136 293 / 136 288 / 138 278 / 132 286 / 131 286 / 132
80 (27) 302 / 138 309 / 140 300 / 137 315 / 137 310 / 139 299 / 133 310 / 132 309 / 133
85 (29) 323 / 139 331 / 140 322 / 138 338 / 139 332 / 140 323 / 134 330 / 132 332 / 134
90 (32) 346 / 141 355 / 142 345 / 140 361 / 139 356 / 140 344 / 135 353 / 133 357 / 135

95 (35) 369 / 142 379 / 143 369 / 141 385 / 141 381 / 141 369 / 136 375 / 134 381 / 136
100 (38) 394 / 143 402 / 144 393 / 142 410 / 142 406 / 143 394 / 137 400 / 136 407 / 137
105 (41) 417 / 145 430 / 145 418 / 143 436 / 143 432 / 143 418 / 139 426 / 137 433 / 138
110 (43) 445 / 146 457 / 146 445 / 144 463 / 145 459 / 145 446 / 140 451 / 139 459 / 140
115 (45) 476 / 148 485 / 147 474 / 145 491 / 146 490 / 145 477 / 141 482 / 141 488 / 141

Fixed Orifice (RFC)

65 (18) 244 / 135 244 / 125 243 / 116 252 / 129 250 / 135 248 / 127 248 / 123 255 / 126

70 (21) 262 / 136 263 / 128 262 / 120 271 / 131 268 / 137 266 / 130 269 / 127 274 / 128

75 (24) 281 / 137 282 / 131 283 / 124 290 / 133 288 / 138 284 / 132 295 / 131 294 / 131

80 (27) 302 / 138 303 / 134 305 / 128 312 / 136 310 / 139 305 / 134 315 / 133 317 / 134

85 (29) 323 / 139 326 / 137 328 / 132 334 / 139 332 / 140 325 / 137 334 / 135 339 / 136

90 (32) 346 / 141 347 / 138 351 / 135 356 / 141 356 / 140 347 / 139 359 / 138 362 / 138

95 (35) 369 / 142 372 / 141 376 / 139 380 / 143 381 / 141 371 / 141 384 / 140 386 / 140
100 (38) 394 / 143 396 / 143 401 / 142 405 / 145 406 / 143 394 / 143 409 / 142 413 / 142
105 (41) 417 / 145 421 / 145 427 / 145 429 / 147 432 / 143 418 / 144 434 / 144 435 / 144
110 (43) 445 / 146 449 / 147 454 / 147 456 / 148 459 / 145 445 / 146 462 / 145 462 / 146
115 (46) 476 / 148 479 / 149 482 / 149 483 / 151 490 / 145 472 / 147 489 / 146 490 / 148

*Values shown are typical pressures; indoor unit match up, indoor air quality equipment, and indoor load will cause the pressures to vary.
**Temperature of the air entering the outside coil.

−018 −024 −030 −036 −042 −048

Liquid / Vapor Liquid / Vapor Liquid / Vapor Liquid / Vapor Liquid / Vapor Liquid / Vapor

the system. Minor variations in these pressures may be due to differences in
installations. Significant deviations could mean that the system is not properly
charged or that a problem exists with some component in the system.

−060−1

Liquid / Vapor

−060−2

Liquid / Vapor

Page 9

Determining Charge Method1.

START: Determine how refrigerant is metered

WHEN TO CHARGE?

 Warm weather best
 Can charge in colder weather

CHARGE METHOD? Determine by:

 Metering device type
 Outdoor ambient temperature

REQUIREMENTS:

 Sufficient heat load in structure
 Indoor temperature between 70-80ºF

(21−26ºC)

 Manifold gauge set connected to unit
 Thermometers:

− to measure outdoor ambient
temperature

− to measure liquid line temperature

− to measure vapor line temperature

(18.3ºC) and

APPROACH OR

SUBCOOLING

TXV

65ºF

Above

64ºF

(17.7ºC) and

Below

WEIGH-IN

FIGURE 12

Which

metering

device?

40ºF

(4.4ºC) and

Above

RFC

39ºF

(3.8ºC) and

Below

WEIGH-INSUPERHEAT

Weigh in Charge

1.Recover the refrigerant from the unit.

2.Conduct leak check; evacuate as previously outlined.

3.Weigh in the unit nameplate charge plus any charge re­quired for linesets differences from 15 feet. (If weighing
facilities are not available, use the subcooling method.)

TABLE 3

Refrigerant Charge per Line Set Lengths

Liquid Line Set

Diameter

3/8 in. (9.5 mm) 3 ounce per 5 ft. (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.

Ounces per 5 feet (g per 1.5 m) adjust

from 15 feet (4.6 m) line set*

Page 10

Superheat RFC Charge

START: Measure outdoor ambient temperature

USE WEIGH-IN METHOD

Weigh-in or remove refriger­ant based upon line length

If refrigerant added or

removed, retest to
confirm that unit is

properly charged

If value is greater than
shown, add refrigerant;
if less than shown,
remove refrigerant.

NOTE − Do not at­tempt to charge sys­tem where a dash ap­pears, system could
be overcharged. Su­perheat is taken at va­por line service port.
Vapor line superheat
must never be less
than 5ºF at the vapor
line service port.

ºF* 50 52 54 56 58 60 62 64 66 68 70 72 74 76
40 15 18 20 23 26 29 32 34 38 41 43 46 48 51
45 13 16 18 21 24 27 30 33 36 39 41 44 46 49
50 11 14 16 19 22 25 28 31 34 37 39 42 44 47
55 9 12141720232730333638404244
60 7 10121518212427303335384043
65 - 6 10 13 16 19 21 24 27 30 33 36 38 41
70 - - 7 1013161921242730333639
75 - - - 6 9 121518212428313437
80 - - - - 5 8 12 15 18 21 25 28 31 35
85 ------811151922263033
90 - - - - - - 5 9 13 16 20 24 27 31
95 -------6101418222529
100 - - - - - - - - 8 12 16 21 24 28
105 --------5913172226
110 ---------611152025
115 ----------8141824

* Dry−bulb temperature (ºF) of entering outdoor ambient air.

BELOW

SHº (Superheat) Values (+/−5ºF)

Wet Bulb (air entering indoor coil)

Ambient 40ºF

Outdoor

(4ºC)?

ABOVE

1.. Confirm proper airflow across coil using figure

11.

2.. Check liquid and vapor line pressures and
compare unit pressures with Normal Operating
Pressures listed in table 2.

(Note: Table 2 is a general guide. Expect minor
pressures variations. Significant differences
may mean improper charge or other system
problem.)

3.. Use SUPERHEAT to correctly charge unit or to
verify the charge is correct.

SUPERHEAT METHOD

4.. Set thermostat to call for heat (must have a
cooling load between 70-80ºF (21−26ºC)

5.. Connect gauge set

6.. When heat demand is satisfied, set thermostat
to call for cooling

7.. Allow temperatures and pressures to stabilize

8.. Measure the vapor line pressure and use the
use value to determine saturation temperature
(table 4 on page 11) SATº =_________

9.. Record vapor line
temperature VAPº =_________

10.. Subtract to determine superheat (SHº):

11.. VAPº − _____ SATº ______ = SHº______

12.. Record the wet bulb temperature (air entering
indoor coil) WB =__________

13.. Record outdoor ambient temperature

14.. Compare results with table to the left

Table 4

HFC−410A Temperature (°F) − Pressure (Psig)

°F Psig °F Psig °F Psig °F Psig °F Psig °F Psig °F Psig °F Psig

32 100.8 48 137.1 63 178.5 79 231.6 94 290.8 11 0 365.0

125 445.9

33 102.9 49 139.6 64 181.6 80 235.3 95 295.1 111 370.0 126 451.8 142 552.3

34 105.0 50 142.2 65 184.3 81 239.0 96 299.4 11 2 375.1 127 457.6 143 559.1

35 107.1 51 144.8 66 187.7 82 242.7 97 303.8 11 3 380.2 128 463.5 144 565.9

36 109.2 52 147.4 67 190.9 83 246.5 98 308.2 11 4 385.4 129 469.5 145 572.8

37 111.4 53 150.1 68 194.1 84 250.3 99 312.7 115 390.7 130 475.6 146 579.8

38 113.6 54 152.8 69 197.3 85 254.1 100 317.2 11 6 396.0 131 481.6 147 586.8

39 115.8 55 155.5 70 200.6 86 258.0 101 321.8 11 7 401.3 132 487.8 148 593.8

40 118.0 56 158.2 71 203.9 87 262.0 102 326.4 11 8 406.7 133 494.0 149 601.0

41 120.3 57 161.0 72 207.2 88 266.0 103 331.0 11 9 412.2 134 500.2 150 608.1

42 122.6 58 163.9 73 210.6 89 270.0 104 335.7 120 417.7 135 506.5 151 615.4

43 125.0 59 166.7 74 214.0 90 274.1 105 340.5 121 423.2 136 512.9 152 622.7

44 127.3 60 169.6 75 217.4 91 278.2 106 345.3 122 428.8 137 519.3 153 630.1

45 129.7 61 172.6 76 220.9 92 282.3 107 350.1 123 434.5 138 525.8 154 637.5

46 132.2 62 175.4 77 224.4 93 286.5 108 355.0 124 440.2 139 532.4 155 645.0

47 134.6 78 228.0 109 360.0 140 539.0

141 545.6

Page 11

Approach TXV Charge

START: Measure outdoor ambient temperature

DO NOT CHARGE UNIT

USE WEIGH-IN METHOD

(Results of charging at low

Weigh-in or remove refriger-

temperatures not reliable)

ant based upon line length

If value is greater than shown (high
approach), add refrigerant; if less
than shown (liquid temp too close to
ambient temp, low approach), remove
refrigerant.

APPº (Approach) Values(F:+/−1.0°; [C: +/−0.6°])

ºF (ºC)* −018 −024 −030 −036 −042 −048 −060
Any 8 (4.4) 8 (4.5) 9 (5.0) 15 (8.3) 10 (5.6) 6 (3.3) 9 (5.0)
*Temperature of air entering outdoor coil

BELOW

Outdoor Am-

bient 65ºF

(18ºC)?

If refrigerant added or

removed, retest to
confirm that unit is

properly charged

ABOVE

1.. Confirm proper airflow across coil using figure

11.

2.. Check liquid and vapor line pressures and
compare unit pressures with Normal Operat­ing Pressures listed in table 2 on page 9.

(Table 2 is a general guide. Expect minor
pressures variations. Significant differences
may mean improper charge or other system
problem.)

3.. Use APPROACH to correctly charge unit or
to verify the charge is correct.

APPROACH METHOD

4.. Set thermostat to call for heat (must have a
cooling load between 70-80ºF (21−26ºC)

5.. Connect gauge set

6.. When heat demand is satisfied, set thermo­stat to call for cooling

7.. Allow temperatures and pressures to stabilize

8.. Record outdoor ambient
temperature AMBº =_________

9.. Record line temp. LIQº = __________

10.. Subtract to determine approach (APPº):

11.. LIQº_____ − AMBº _____ = APPº_____

12.. Compare results with table to the left

Subcooling TXV Charge

START: Measure outdoor ambient temperature

DO NOT CHARGE UNIT

USE WEIGH-IN METHOD

(Results of charging at low

Weigh-in or remove refriger-

temperatures not reliable)

ant based upon line length

If refrigerant added or

removed, verify

charge using the

approach method

If value is greater than

shown, remove
refrigerant; if less than
shown, add refrigerant

SCº (Subcooling) Values (F:+/−1.0°; [C: +/−0.6°])

ºF (ºC)* −018 −024 −030 −036 −042 −048 −060
Any 8 (4.4) 8 (4.4) 7 (3.8) 4 (2.2) 8 (4.4) 10 (5.6) 7 (3.9)
*Temperature of air entering outdoor coil

BELOW

BLOCK OUTDOOR COIL
[sometimes necessary with lower temperatures]
Use cardboard or plastic sheet to restrict the
airflow through the outdoor coil to achieve pres­sures from 325−375 psig (2240−2585 kPa).
Higher pressures are needed to check charge.
Block equal sections of air intake panels and
move coverings sideways until the liquid pres­sure is in the above noted ranges.

Outdoor Am-

bient 65ºF

(18ºC)?

ABOVE

1.. Confirm proper airflow across coil using figure

11.

2.. Check liquid and vapor line pressures and
compare unit pressures with Normal Operat­ing Pressures listed in table 2.

(Table 2 is a general guide. Expect minor pres­sures variations. Significant differences may
mean improper charge or other system prob­lem.)

3.. Use SUBCOOLING to correctly charge unit or
to verify the charge is correct.

SUBCOOLING METHOD

4.. Set thermostat to call for heat (must have a

cooling load between 70-80ºF (21−26ºC)

5.. Connect gauge set

6.. Measure outdoor ambient temperature

7.. When heat demand is satisfied, set thermo-

stat to call for cooling

8.. Allow temperatures and pressures to stabilize

[NOTE − IF NECESSARY, block outdoor coil
to maintain 325 − 375 psig]

9.. Record line temp. LIQº = ______

10.. Measure liquid line pressure and use the val­ue to determine saturation temperature
(table 4 on page 11) SATº = ______

11.. Subtract to determine subcooling (SCº):

12.. SATº_____ − LIQº _____ = SCº _____

13.. Compare results with table to the left.

+

Page 12

V − MAINTENANCE

WARNING

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

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

1.Make sure power is off before cleaning. Clean and inspect
outdoor coil. The coil may be flushed with a water hose.

The outdoor coil is protected by an inner mesh screen
and a wire cage (see figure 13). If debris has collected
between the mesh screen and the coil and cannot be
dislodged by spraying unpressurized water from inside
coil surface to the outside, the mesh may be removed by
first removing the top of the unit which will allow for re­moval of the wire cage.

Then, using pliers to grip the head of the push pins, pull
straight out to extract the push pins along one side of the
coil. If necessary, remove the push pins along the back
of the unit; it is usually unnecessary to fully remove the
inner mesh screen.

Drape the mesh screen back and wash the coil. When
all the debris has been removed from the coil, reinstall
the mesh screen by positioning it in its original position
and reinserting the push pin. No tool is required to push
the pin back into the same slot in the fins.

If the push pin is loose and tends not to stay in place,
brush the fins with a fin brush (22 fins/in). Line up the
push pin a couple fins to the right or left of the original
hole and re−insert the pin.

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

3.Visually inspect connecting lines and coils for evidence of
oil leaks.

4.Check wiring for loose connections.

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

6.Check amp−draw outdoor fan motor.

Unit nameplate _________ Actual ____________ .

NOTE − If owner reports insufficient cooling, the unit should
be gauged and refrigerant charge checked. See refrigerant
charging section.

9 pins used on

−048 and −060; 6
pins all others

PUSH PIN

MESH SCREEN

Figure 13

Indoor Coil

1.Clean coil, if necessary.

2.Check connecting lines and coils for signs of oil leaks.

3.Check the condensate pan line and clean if necessary.

Indoor Unit

1.Clean or change filters.

2.Adjust blower speed for cooling. The pressure drop over the
coil should be measured to determine the correct blower
CFM. Refer to the unit information service manual for
pressure drop tables and procedure.

3.Check all wiring for loose connections

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

5.Check amp−draw on blower motor.
Unit nameplate_________ Actual ____________.

Page 13

VI − WIRING DIAGRAMS AND SEQUENCE OF OPERATION

13ACX

NOTE− The thermostat used may be electromechanical or electronic.
NOTE− Transformer in indoor unit supplies power (24 VAC) to the thermostat and outdoor unit controls.

COOLING:

1− Cooling demand initiates at Y1 in the thermostat.
2− 24VAC from indoor unit (Y1) energizes the TOC timed off control (if used) which energizes contactor K1.
3− K1-1 N.O. closes, energizing compressor (B1) and outdoor fan motor (B4).
4− Compressor (B1) and outdoor fan motor (B4) begin immediate operation..

END OF COOLING DEMAND:

5− Cooling demand is satisfied. Terminal Y1 is de-energized and the TOC( if used) begins its off cycle timing.
6− Compressor contactor K1 is de-energized.
7− K1-1 opens and compressor (B1) and outdoor fan motor (B4) are de-energized and stop immediately.

Page 14