Lennox Value 10ACB Series User manual

3DJH 
£
PRODUCT LITERATURE
¤ 1998 Lennox Industries Inc.
Dallas, Texas
VALUE 10
TM
CONDENSING UNIT
Value 10 condensing units are designed for expansion
valve (TXV) and RFC systems. Refer to Lennox engi-
neering handbook for expansion valve kits which must
be ordered separately.
SHIPPING AND PACKING LIST
1-- Assembled 10ACB condensing unit
1-- 45 E copper street elbow
1-- RFCIV refrigerant metering device (bullet)
1-- Coupling -- 5/16 x 3/8 (18, 24, 30)
Check unit for shipping damage. Consult last carrier
immediately if damage is found.
GENERAL INFORMATION
These instructions are intended as a general guide and
do not supersede national or local codes in any way.
Authorities having jurisdiction should be consulted be-
fore installation.
IMPORTANT
The Clean Air Act of 1990 bans the intentional
venting of refrigerant (CFCs and HCFCs) as of July
1, 1992. Approved methods of recovery, recycling
or reclaiming must be followed. Fines and/or in-
carceration may be levied for non--compliance.
INSTALLATION
INSTRUCTIONS
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70
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1--1/2 through 5 ton
503,800M
2/98
Supersedes 503,755M
TABLE OF CONTENTS
VALUE 10 CONDENSING UNIT 1.....................
SHIPPING AND PACKING LIST 1......................
GENERAL INFORMATION 1..........................
10ACB UNIT DIMENSIONS 2.........................
SETTING THE UNIT 3................................
ELECTRICAL 3......................................
PLUMBING 4.......................................
REFRIGERANT METERING DEVICE 4..................
MANIFOLD GAUGE SET 5...........................
LIQUID & SUCTION LINE SERVICE VALVES 5..........
LEAK TESTING 6....................................
EVACUATION 7.....................................
START-UP 8........................................
CHARGING CONSIDERATIONS 8.....................
CHARGING FOR RFC SYSTEMS 9....................
CHARGING FOR TXV SYSTEMS 10...................
SYSTEM OPERATION 10.............................
MAINTENANCE 11..................................
10ACB CHECK POINTS 12............................
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
WARNING
Product contains fiberglass wool.
Disturbing the insulation in this product during
installation, maintenance, or repair will expose
you to fiberglass wool. Breathing this may cause
lung cancer. (Fiberglass wool is known to the
State of California to cause cancer.)
Fiberglass wool may also cause respiratory, skin,
and eye irritation.
To reduce exposure to this substance or for further
information, consult material safety data sheets
available from address shown below, or contact
your supervisor.
Lennox Industries Inc.
P.O. Box 799900
Dallas, TX 75379--9900
/LWKR 86$

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10ACB UNIT DIMENSIONS--INCHES (MM)
SIDE VIEW
SUCTION &
LIQUID LINE
CONNECTION
INLET
AIR
INLET
AIR
DISCHARGE AIR
SIDE VIEW
TOP VIEW
A
OUTDOOR
COIL FAN
COMPRESSOR
INLET AIR
INLET AIR
SUCTION LINE
CONNECTION
B
24-1/4
(616)
3/4 (19)
2-3/4 (70)
24-1/4
(616)
ELECTRICAL
INLETS
LIQUID LINE
CONNECTION
Model No. A B
10ACB12
10ACB18 in. 25 24-1/4
10ACB18
10ACB24
10ACB30 mm 635 616
10ACB36
10ACB42
10ACB48
in. 33 32-1/4
10ACB48
10ACB60
10ACB62 mm 838 819

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SETTING THE UNIT
Refer to unit dimensions on page 2 for sizing mounting
slab, platforms or supports. Refer to figure 1 for instal-
lation clearances.
INSTALLATION CLEARANCES
FIGURE 1
36
(914 mm)
*36
(914 mm)
36
(914 mm)
NOTE48 inch clearance required on top of unit.
*NOTEOne side must be 36 inches. Two side may be 12.
*36
(914 mm)
Slab Mounting
When installing unit at grade level, install on a level
slab high enough above gradeto allow adequatedrain-
age of water. Top of slab should be located so run--off
water from higher ground will not collect around unit.
Roof Mounting
Install unit at a minimum of 4 inches above the surface
of the roof. Care must be taken to ensure weight of unit
is properly distributed over roof joists and rafters. Ei-
ther redwood or steel supports are recommended.
ELECTRICAL
In the U.S.A., wiring must conform with current local
codes and the current National Electric Code (NEC). In
Canada, wiring must conform with current local codes
and the current Canadian Electrical Code (CEC). Refer to
the furnace or blower coil installation instructions for
additional wiring application diagrams and refer to
unit rating plate for minimum circuit ampacity and
maximum overcurrent protection size.
WARNING
Unit must be grounded in accordance with nation-
al and local codes. Electric Shock Hazard.
Can cause injury or death.
Line Voltage
To facilitate conduit, a hole is provided in bottom of the
control box. Connect conduit to hole in control box
with proper conduit fitting.
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24V, Class II Circuit
24V, Class II Circuit connections are made up in the low
voltage junction box. Refer to figure 2 for field wiring
diagram.
NOTE -- A complete unit wiring diagram is located in-
side the unit control box cover.
TO
COOLING
SPEED
TO
HEATING
SPEED
Y1 RC
WG RH
CONDENSING UNIT TYPICAL INDOOR UNIT
ROOM THERMOSTAT
POWER
GROUND
PER NATIONAL
AND LOCAL
CODES
24v
TRANSFORMER
24V
CLASS II
JUNCTION
BOX
TO
HEATING
CONTROLS
TO 24V CLASS II POWER SOURCE
-- 20 VA MINIMUM
K3 INDOOR BLOWER RELAY
NOTE--IF INDOOR UNIT IS NOT EQUIPPED WITH
BLOWER RELAY, IT MUST BE FIELD PROVIDED
AND INSTALLED (P--8--3251 OR EQUIVALENT)
NOTE--SEE UNIT WIRING DIAGRAM
FOR POWER SUPPLY CONNECTIONS. 24V CLASS II INSTALLED AT FACTORY
24V CLASS II FIELD INSTALLED
FIGURE 2
Y1
C
C
T1
R
W1
G
C
W2
10ACB TYPICAL FIELD WIRING DIAGRAM

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PLUMBING
Field refrigerant piping consists of liquid and suction
lines from the condensing unit (sweat connections) to
the indoor evaporator coil (flare or sweat connections).
Use Lennox L10 (flare) or L15 (sweat, non-flare) series
line sets as shown in table 1 or use field-fabricated re-
frigerant lines. Refer to unit information manual piping
section for proper size, type and application of field--
fabricated lines.
Sweat Connection Procedure
1-- Ends of refrigerant lines must be cut square, free
from nicks or dents, deburred. Pipe must remain
round, do not pinch end of line.
2-- Wrap a wet cloth around the liquid line valve body
and copper tube stub to protect from heat damage
during brazing. Wrap another wet cloth underneath
the liquid valve to protect the base paint.
3-- Quench the joints with a wet cloth to prevent possible
heat damage to the valve core and opening port.
4-- A field provided filter drier should be installed as
close as possible to the expansion device.
REFRIGERANT METERING DEVICE
10ACB units are applicable to either RFCIV or an expan-
sion valve system. See indoor coil installation instruc-
tions and the Lennox engineering handbook for ap-
proved RFC and TXV match-ups and application
information. Table 1 lists 10ACB unit liquid and suction
line sizes and corresponding line sets.
TABLE 1
REFRIGERANT LINE KITS
UNIT LIQUID
LINE SUCTION LINE L10
LINE SETS
10ACB24
10ACB30
10ACB42
3/8 in
(10 mm) 3/4 in. (19 mm)
L10--41
20 ft. -- 50 ft.
(6m--15m)
10ACB18 5/16 in*
(8 mm)
3/8 in
(10 mm)
L10--65
30 ft. -- 50 ft.
(9m--15m)
L10--21
20 ft. -- 50 ft.
(6m--15m)
5/8 in
(16 mm)
7/8 in.
(22 mm)
10ACB48
3/8 in
(10 mm) 1--1/8 in. (29 mm) FIELD
FABRICATED
10ACB60
*Use reducer supplied in bag assembly.
L15
LINE SETS
L15--41
20 ft. -- 50 ft.
(6m--15m)
L15--65
30 ft. -- 50 ft.
(9m--15m)
L15--21
20 ft. -- 50 ft.
(6m--15m)
FIELD
FABRICATED
10ACB36
10ACB62
NOTE -- Line length should be no greater than 50 feet
(15.2 m). Select line set diameters from table 1 to en-
sure oil return to compressor.
RFC Systems
10ACB units are shipped with an RFCIV metering de-
vice. Replace existing RFCIV in indoor unit with RFCIV
supplied with the outdoor unit. Place the supplied
RFCIV sticker on indoor cabinet after installation. See
table 2 for size of RFCIV bullet shipped in each 10ACB
unit. In cases of non-traditional applications, RFCIV
bullet shipped may not be appropriate. Refer to the in-
door coil installation instructions and the engineering
handbook for specific orifice information.
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10ACB UNIT RFCIV PART # RFCIV DRILL SIZE
10ACB12 42J35 0.047
10ACB18 42J39 0.055
10ACB24 66J87 0.062
10ACB30 42J45 0.067
10ACB36 42J48 0.073
10ACB42 42J52 0.080
10ACB48 42J54 0.084
10ACB60 42J58 0.092
RFCIV bullet is installed as shown in figure 3. Take care
not to twist cap tubes when loosening seal nut from
orifice body.
RF CIV INSTALLATION
DISTRIBUTOR
BULLET
ORIFICE
ORIFICE
BODY
SEAL
NUT
FIGURE 3
SWEAT
CONNECTION

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Expansion Valve Systems
Expansion valves equipped with either Chatleff or
flare type fittings are available from Lennox. Refer to
the indoor coil installation instructions or the engineer-
ing handbook for applicable expansion valves for use
with specific match--ups.
If an expansion valve application is desired with indoor
coil product shipped with an RFCIV orifice, the RFCIV re-
strictor must be removed before installing the expan-
sion valve.
IMPORTANT
Failure to remove RFCIV when installing an expan-
sion valve to the indoor coil will result in improper
operation and damage to the system.
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A manifold gauge set equipped with low loss hoses
should be used when checking unit charge. A manifold
gauge set with anything other than low loss hose
should not be used.
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The liquid line and suction line service valves (figures 4
and 5) and gauge ports are accessible from outside the
unit. The service ports are used for leak testing, eva-
cuating, charging and checking charge.
The valve is equipped with a service port. A schrader
valve is factory installed. A service port cap is supplied to
protect the schrader valve from contamination and serve
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.
Tighten finger tight, then an additional 1/6 turn.
To Open Liquid or Suction Line Service Valve:
1-- Remove stem cap with an adjustable wrench.
2-- Using service wrench and 5/16 hex head extension
back the stem out counterclockwise until the valve
stem just touches the retaining ring.
Do not attempt to backseat this valve. Attempts to
backseat this valve will cause snap ring to explode
from valve body under pressure of refrigerant.
Personal injury and unit damage will result.
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3-- Replace stem cap tighten firmly. Tighten finger tight,
then tighten an additional 1/6 turn.
FIGURE 4
LIQUID LINE SERVICE VALVE (VALVE OPEN)
SCHRADER
VALVE
SERVICE
PORT
SERVICE
PORT
CAP
INSERT HEX
WRENCH HERE
TO INDOOR
COIL
TO OUTDOOR
COIL
STEM CAP
SCHRADER VALVE OPEN
TO LINE SET WHEN VALVE
IS CLOSED (FRONT SEATED)
SERVICE
PORT
SERVICE
PORT CAP
RETAINING RING STEM CAP
INSERT HEX
WRENCH HERE
LIQUID LINE SERVICE VALVE (VALVE CLOSED)
(VALVE FRONT SEATED)
TO OUTDOOR
COIL
TO INDOOR
COIL
To Close Liquid or Suction Line Service Valve:
1-- Remove stem cap with an adjustable wrench.
2-- Using service wrench and 5/16 hex head exten-
sion, turn stem clockwise to seat the valve. Tighten
firmly.

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3-- Replace stem cap. Tighten finger tight, then tighten
an additional 1/6 turn.
FIGURE 5
SUCTION LINE SERVICE VALVE (VALVE OPEN)
SCHRADER
VALVE
SERVICE PORT
SERVICE PORT
CAP
INSERT HEX
WRENCH HERE
TO INDOOR
COIL
TO OUTDOOR
COIL
STEM CAP
SCHRADER VALVE OPEN
TO LINE SET WHEN VALVE IS
CLOSED (FRONT SEATED)
SERVICE
PORT
SERVICE PORT
CAP
RETAINING RING STEM CAP
INSERT HEX
WRENCH HERE
SUCTION LINE SERVICE VALVE (VALVE CLOSED)
(VALVE FRONT
SEATED)
TO INDOOR
COIL
TO OUTDOOR
COIL
5 --Ton Suction Line (Ball Type) Service Valve
A ball-type full service valve only is used on five ton units
(10ACB60/62). These suction line service valves function
the same way, differences are in construction. Valves are
not rebuildable. If a valve has failed it must be re-
placed. A ball valve valve is illustrated in figure 6.
The ball valve is equipped with a service port. A
schrader valve is factory installed. A service port cap
is supplied to protect the schrader valve from con-
tamination and assure a leak free seal.
SUCTION LINE (BALL TYPE) SERVICE VALVE
(VALVE OPEN)
FIGURE 6
SCHRADER VALVE
SERVICE PORT
SERVICE PORT
CAP
STEM CAP
STEM
USE ADJUSTABLE WRENCH
ROTATE STEM CLOCKWISE 90 E TO CLOSE
ROTATE STEM COUNTER-CLOCKWISE 90 E TO OPEN
BALL
(SHOWN OPEN)
TO OUTDOOR COIL
TO INDOOR COIL
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After the line set has been connected to the indoor and
outdoor units, the line set connections and indoor unit
must be checked for leaks.
WARNING
Never use oxygen to pressurize refrigeration or air
conditioning system. Oxygen will explode on con-
tact with oil and could cause personal injury. When
using high pressure gas such as nitrogen or CO
2
for
this purpose, be sure to use a regulator that can
control the pressure down to 1 or 2 psig.
Using an Electronic Leak Detector or Halide
1-- Connect cylinder of HCFC-22 to center port of man-
ifold gauge set.
2-- With both manifold valves closed, open the valve
on the HCFC-22 bottle (vapor only).
3-- Open the high pressure side of the manifold to al-
low HCFC-22 into the line set and indoor unit.
Weigh in a trace amount of HCFC-22. (A trace
amount is a maximum of 2 ounces or 3 poun ds
pressure.) Close the valve on the HCFC-22 bottle
and the valve on the high pressure side of the man-
ifold gauge set. Disconnect HCFC-22 bottle.
4-- Connect a cylinder of nitrogen with a pressure reg-
ulating valve to the center port of the manifold
gauge set.

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5 -- Connect the high pressure hose of the manifold
gauge set to the service port of the suction valve.
(Normally, the high pressure hose is connected to
the liquid line port, however, connecting it to the
suction port better protects the manifold gauge set
from high pressure damage.)
6-- Adjust nitrogen pressure to 150 psig. Open the
valve on the high side of the manifold gauge set
which will pressurize line set and indoor unit.
7-- After a short period of time, open a refrigerant port
to make sure the refrigerant added is adequate to be
detected. (Amounts of refrigerant will vary with line
lengths.) Check all joints for leaks. Purge nitrogen
and HCFC-22 mixture. Correct any leaks and re-
check.
(9$&8$7,1*
Evacuating the system of non--condensables is critical
for proper operation of the unit. Non--condensables are
defined as any gas that will not condense under temper-
atures and pressures present during operation of an air
conditioning system. Non--condensables and water va-
por combine with refrigerant to produce substances
that corrode copper piping and compressor parts.
1-- Connect manifold gauge set to the service valve
ports as follows: low pressure gauge to suction
line service valve; high pressure gauge to liquid
line service valve.
2-- Connect the vacuum pump (with vacuum gauge)
to the center port of the manifold gauge set.
3-- Open both manifold valves and start vacuum
pump.
4-- Evacuate the line set and indoor unit to an absolute
pressure of 23mm of mercury or approximately 1
inch of mercury. During the early stages of evacua-
tion, it is desirable to close the manifold gauge
valve at least once to determine if there is a rapid
rise in absolute pressure . A rapid rise in pressure
indicates a relatively large leak. If this occurs, the
leak testing procedure must be repeated.
NOTE -- The term absolute pressure means the to-
tal actual pressure within a given volume or sys-
tem, above the absolute zero of pressure. Absolute
pressure in a vacuum is equal to atmospheric pres-
sure minus vacuum pressure.
5-- When the absolute pressure reaches 23mm of mer-
cury, 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 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.
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Danger of Equipment Damage.
Avoid deep vacuum operation. Do not use com-
pressors to evacuate a system.
Extremely low vacuums can cause internal arcing
and compressor failure.
Damage caused by deep vacuum operation will
void warranty.
6-- Shut off the nitrogen cylinder and remove the man-
ifold gauge hose from the cylinder. Open the man-
ifold gauge valves to release the nitrogen from the
line set and indoor unit.
7-- 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 pres-
sure does not rise above .5mm of mercury within a
20 minute period after shutting off the vacuum
pump and closing the manifold gauge valves.
8-- Depending on the equipment used to determine
the vacuum level, the following units are equiva-
lent to absolute pressure of .5mm of mercury or
500 microns.
9-- When the absolute pressure requirement above has
been met, disconnect the manifold hose from the
vacuum pump and connect it to an upright bottle of
HCFC-22 refrigerant. Open the manifold gauge
valves to break the vacuum in the line set and in-
door unit. Close manifold gauge valves and shut off
HCFC-22 bottle and remove manifold gauge set.

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IMPORTANT
Crankcase heater (used on 3--1/2, 4 and 5 ton
units) should be energized 24 hours before unit
start--up to prevent compressor damage as a re-
sult of slugging.
1-- Rotate fan to check for frozen bearings or binding.
2-- Inspect all factory and field-installed wiring for
loose connections.
3-- After evacuation is complete, open liquid line and
suction line service valves to release refrigerant
charge (contained in condensing unit) into the sys-
tem.
4-- Replace stem caps and secure finger tight, then
tighten an additional (1 /6) one-sixth of a turn.
5-- Check voltage supply at the disconnect switch. The
voltage must be within the range listed on unit
nameplate. If not, do not start the equipment until
the power company has been consulted and the
voltage condition corrected.
6-- Set the thermostat for cooling demand, turn on
power to evaporator blower and close condensing
unit disconnect switch to start unit.
7-- Recheck voltage with unit running. Power must be
within range shown on nameplate. Check amper-
age draw of unit. Refer to unit nameplate for cor-
rect running amps.
&+$5*,1* &216,'(5$7,216
Units are factory charged with the amount of HCFC-22
refrigerant indicated on the unit rating plate. This
charge is based on a matching indoor coil and outdoor
coil with 20 ft. (6.1m) line set. For varying lengths of line
set, refer to table 3 for refrigerant charge adjustment. A
blank space is provided on the rating plate to list the ac-
tual field charge.
Liquid Line
Set Diameter Ozs. per 5 ft. (ml per mm) adjust
from 20 ft. (6.1m) line set*
3/8 in.
(10mm)
5/16 in.
(8mm) 2 ounce per 5 ft.
(57ml per 1.5m)
3 ounce per 5 ft.
(85ml per 1.5m)
*If line length is greater than 20 ft. (6.1m), add this amount. If
line length is less than 20 ft. (6.1m), subtract this amount.
TABLE 3
If the system is void of refrigerant, the recommended
and most accurate method of charging is to weigh the
refrigerant into the unit according to the total amount
shown on the unit nameplate. This may be done after
any leaks have been repaired. If weighing facilities are
not available or if unit is just low on charge, use one of
the procedures outlined.
Charging a condensing unit is recommended during
warm weather. However, applications arise in which
charging must occur in the colder months. The way the
unit is charged depends on the units refrigerant me-
tering device and the outdoor ambient temperature .
For RFC systems, weighing in the charge and subcooling
are two acceptable means of charging under certain
conditions. For installations of an RFC system where the
outdoor ambient is less than 65 E F(18 E C), weighing in the
charge is the best method. However, in installations
where the outdoor ambient is 65 E F(18 E C) or above, sub-
cooling is the best method.
Weighing in the charge and the approach method are
the two recommended procedures for charging the
10ACB using an expansion valve system for refrigerant
metering. The difference between the two involves the
outdoor ambient temperature. For expansion valve
systems where the outdoor ambient temperature is
60 E F(16 E C) or above, the approach method may be
used. For expansion valve systems where the outdoor
ambient temperature is below 60 E F(16 E C), weighing in
the charge is recommended.

3DJH 
TABLE 4
NORMAL OPERATING PRESSURES IN PSIG (LIQUID AND SUCTION +/-- 10 PSIG)*
MODE
OUT. COIL
ENTERING
10ACB12 10ACB18 10ACB24 10ACB30 10ACB36 10ACB42 10ACB48 10ACB60 10ACB62
MODE
ENTERING
AIR TEMP.
q F( q C) LIQ. SUC. LIQ. SUC. LIQ. SUC. LIQ. SUC. LIQ. SUC. LIQ. SUC. LIQ. SUC. LIQ. SUC. LIQ. SUC.
65 (18.3) 145 71 155 65 160 65 168 63 176 62 162 68 157 69 153 66 159 64
75 (23.9) 167 77 181 70 188 70 197 68 203 66 185 72 182 72 180 71 188 68
RFCIV
85 (29.4) 192 81 208 75 216 74 227 73 233 70 210 73 204 73 210 74 219 72
95 (35.0) 221 84 238 80 247 78 258 77 266 74 252 76 244 76 245 77 253 75
105 (40.6) 253 87 270 84 280 82 292 80 299 77 287 79 278 79 279 79 287 76
65 (18.3) 140 79 159 73 164 71 173 71 179 68 157 71 158 70 142 73 151 69
75 (23.9) 161 80 183 75 189 73 199 73 205 70 187 73 182 72 168 75 179 71
TXV
85 (29.4) 189 81 209 77 217 75 228 75 235 72 217 74 205 73 202 76 211 73
95 (35.0) 220 83 238 80 247 78 258 77 266 74 255 76 246 76 245 77 249 74
105 (40.6) 254 84 269 82 279 80 292 79 299 77 289 77 280 79 280 78 286 75
*These are typical pressures only. Indoor evaporator match up, indoor air quality and evaporator load will cause the pressures to vary.
IMPORTANT
Use table 4 as a general guide for performing main-
tenance checks. Table 4 is not a procedure for
charging the system. Minor variations in these
pressures may be expected 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 sys-
tem. Used prudently, table 4 could serve as a useful
service guide.
Before charging the unit, follow the procedure below
to determine: the liquid line temperature and the out-
door ambient temperature.
1 -- Connect manifold gauge set to service valves: low
pressure gauge to suction valve service port; high
pressure gauge to liquid valve service port. Con-
nect the center manifold hose to an upright bottle
of HCFC-22. Close manifold gauge set valves.
2 -- Set the room thermostat to call for heat. This will
create the necessary load for properly charging the
system in the cooling cycle.
3 -- Record the outdoor ambient temperature. For
greater accuracy, use the same electronic ther-
mometer to measure liquid temperature.
4 -- When thermostat demand has been satisfied,
switch to cooling mode with a set point of 68 E F
(20 E C). When pressures have stabilized, record the
liquid line temperature.
5 -- The outdoor temperature will determine which
charging method to use. Proceed with the ap-
propriate charging procedure below.
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Weighing in the Charge Method
RFC Systems, < 65 E F
(18 E C) Outdoor Temp
1-- Recover the refrigerant from the unit.
2-- Conduct a leak check, then evacuate as previously
outlined.
3-- Weigh in the factory charge as shown on the out-
door units rating plate.
The Subcooling Method
RFC Systems, > 65
E F (18 E C) Outdoor Temp
1-- With the manifold gaugehose still on the liquid ser-
vice port and the unit operating stably, record the
liquid line temperature.
2-- At the same time, record the liquid line pressure
reading.
3-- Using a temperature/pressure chart for HCFC-22,
determine the saturation temperature for theliquid
line pressure reading.

3DJH 
4-- Subtract the liquid line temperature from the satu-
ration temperature (according to the chart) to de-
termine subcooling. (Saturation temperature --
Liquid line temperature = Subcooling)
5-- Compare the subcooling value with those in table
5. If subcooling is greater than shown, some refrig-
erant must be recovered. If subcooling is less than
shown, some refrigerant must be added.
TABLE 5
SUBCOOLING FOR RFC SYSTEMS
OUTDOOR
TEMP
LIQUID SUBCOOLING [+ 1 E F (.6 E C)]
TEMP.
E F( E C) 012 018 024 030 036 042 048 060
60
(16) 14 (7.8) 17 (9.5) 18 (10) 18 (10) 14 (8) 14 (8) 12 (6.7) 14 (8)
65
(18) 13 (7.2) 16 (8.9) 16 (8.9) 17 (9.5) 13 (7.8) 13 (7.8) 11 (6.1) 14 (8)
70
(21) 12 (6.7) 15 (8.3) 14 (7.8) 16 (8.9) 12 (6.7) 13 (7.8) 10 (5.6) 13 (7.8)
75
(24) 10 (5.6) 14 (7.8) 12 (6.7) 15 (8.3) 10 (5.6) 12 (6.7) 9 (5) 13 (7.8)
80
(27) 9 (5) 13 (7.2) 11 (6.1) 14 (8) 9 (5) 11 (6.1) 9 (5) 12 (6.7)
85
(29) 8 (4.5) 12 (6.7) 10 (5.6) 13 (7.8) 8 (4.4) 10 (5.6) 9 (5) 12 (6.7)
90
(32) 7 (3.9) 11 (6.1) 9 (5) 12 (6.7) 7 (3.9) 10 (5.6) 8 (4.5) 12 (6.7)
95
(35) 6 (3.3) 9 (5) 8 (4.5) 11 (6.1) 6 (3.3) 9 (5) 8 (4.5) 12 (6.7)
100
(38) 4 (2.2) 8 (4.5) 7 (3.9) 10 (5.6) 5 (2.8) 9 (5) 8 (4.5) 11 (6.1)
105
(41) 2 (1.1) 7 (3.9) 6 (3.3) 9 (5) 4 (2.2) 9 (5) 7 (3.9) 10 (5.6)
110
(43) 2 (1.1) 6 (3.3) 6 (3.3) 7 (3.9) 3 (1.7) 8 (4.5) 7 (3.9) 9 (5)
115
(45) 1 (0.6) 5 (2.8) 5 (2.8) 5 (2.8) 2 (1.1) 7 (3.9) 6 (3.3) 8 (4.5)
Note -- For best results, the same electronic thermometer should be
used to check both outdoor ambient and liquid temperatures.
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Weighing in the Charge
TXV Systems, < 60 E F
(16 E C) Outdoor Temp
1-- Recover the refrigerant from the unit.
2-- Conduct a leak check, then evacuate as previously
outlined.
3-- Weigh in the factory charge as shown on the out-
door units rating plate.
The Approach Method
TXV Systems, > 60
E F (16 E C) Outdoor Temp
Having taken the outdoor ambient and liquid line tem-
perature readings, subtract the outdoor ambient tem-
perature from the liquid line temperature to determine
the Approach temperature. (Liquid Line E F( E C) -- Out-
door Ambient E F( E C) = Approach Temperature.) The
resulting difference (Approach temperature) should
agree with the values given in table 6. If not, add refrig-
erant to lower the approach temperature or recover re-
frigerant from the system to increase the approach
temperature.
TABLE 6
APPROACH METHOD
MODEL
NO. APPROACH TEMPERATURE
LIQUID LINE -- OUTDOOR AMBIENT
E F( E C)
10ACB12 7 (3.9)
10ACB18 5 (2.8)
10ACB24 9 (5)
10ACB30 10 (5.6)
10ACB36 12 (6.7)
10ACB42 14 (8)
10ACB48 13 (7.2)
10ACB60 12 (6.7)
10ACB62 12 (6.7)
Note -- For best results, the same electronic thermometer should be
used to check both outdoor ambient and liquid temperatures.
6<67(0 23(5$7,21
Condensing unit and indoor blower cycle on demand
from room thermostat. When thermostat blower
switch is switched to ON position, indoor blower oper-
ates continuously.
Crankcase Heater
Three and one-half, four and five ton units are equipped
with internal self-regulating crankcase heaters.
Compressor Start Kit
Three and one-half, four and five ton single-phase units
have internal start components and do not require field
installation of a compressor start kit.
Timed-Off Control (Option Units ONLY)
Option units are factory-equipped with a timed-off
control which helps equalize system pressures that al-
lows the compressor to start in an unloaded condition
as well as preventing compressor short-cycling. The
timed-off control delays compressor start-up for five
minutes on thermostat demand. Mounted in the con-
trol box, the control is wired between thermostat ter-
minal Y and the compressor contactor.
High and Low Pressure Switches
(International and Option Units ONLY)
10ACB international and option units are factory-
equipped with both high and low pressure switches.
The pressure switches are located on the valve cores in
the liquid line to allow easy access. The manually reset
high pressure switch protects the system from high
pressure conditions as a result of a fan failure or a