£
INSTALLATION
PRODUCT LITERATURE
¤
1998 Lennox Industries Inc.
Dallas, Texas
VALUE 10TMCONDENSING UNIT
V alue 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.
INSTRUCTIONS
9DOXH
$&% &RQGHQVLQJ 8QLWV
&21'(16,1* 81,76
1--1/2 through 5 ton
503,800M
2/98
Supersedes 503,755M
TABLE OF CONTENTS
VALUE 10 CONDENSING UNIT 1.....................
SHIPPING AND PACKING LIST 1......................
GENERAL INFORMATION 1..........................
10ACB UNIT DIMENSIONS 2.........................
SETTING THE UNIT 3................................
ELECTRICAL 3......................................
PLUMBING 4.......................................
REFRIGERANT METERING DEVICE 4..................
MANIFOLD GAUGE SET 5...........................
LIQUID & SUCTION LINE SERVICE VALVES 5..........
LEAK TESTING 6....................................
EVACUATION 7.....................................
START-UP 8........................................
CHARGING CONSIDERATIONS 8.....................
CHARGING FOR RFC SYSTEMS 9....................
CHARGING FOR TXV SYSTEMS 10...................
SYSTEM OPERATION 10.............................
MAINTENANCE 11..................................
10ACB CHECK POINTS 12............................
70
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/LWKR 86$
SHIPPING AND PACKING LIST
1-- Assembled 10ACB condensing unit
1-- 45Ecopper 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 generalguide and
do not supersede national or local codes in any way.
Authorities having jurisdiction should beconsulted be-
fore installation.
IMPORTANT
The Clean Air Act of 1990 bans the intentional
venting of refrigerant (CFCs and HCFCs)as ofJuly
1, 1992. Approved methods of recovery, recycling
or reclaiming must be followed. Fines and/or in-
carceration may be levied for non--compliance.
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 forfurther
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
3DJH
10ACB UNIT DIMENSIONS--INCHES (MM)
10ACB18
INLET AIR
INLET
AIR
INLET AIR
TOP VIEW
24-1/4
(616)
INLET
AIR
B
SUCTION LINE
CONNECTION
LIQUID LINE
CONNECTION
A
ELECTRICAL
INLETS
OUTDOOR
COIL FAN
COMPRESSOR
SUCTION &
LIQUID LINE
CONNECTION
24-1/4
(616)
DISCHARGE AIR
SIDE VIEW
10ACB12
10ACB18
10ACB24
10ACB30
10ACB36
10ACB42
10ACB48
10ACB60
10ACB62
2-3/4 (70)
3/4 (19)
SIDE VIEW
Model No. A B
in. 25 24-1/4
mm 635 616
in. 33 32-1/4
mm 838 819
3DJH
SETTING THE UNIT
Refer to unitdimensions on page 2 for sizing mounting
slab, platforms or supports. Refer to figure 1 for instal-
lation clearances.
INSTALLATION CLEARANCES
36
(914 mm)
Roof Mounting
Install unit at a minimum of 4 inches above the surface
of the roof. Care must be taken to ensure weight ofunit
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.
36
(914 mm)
*36
(914 mm)
*36
(914 mm)
NOTE48 inch clearance required on top of unit.
*NOTEOne side must be 36 inches. Two side may be 12.
FIGURE 1
Slab Mounting
When installing unit at grade level, install on a level
slab high enough above gradeto allow adequatedrain-
age of water.
water from higher ground will not collect around unit.
NOTE--SEE UNIT WIRING DIAGRAM
FOR POWER SUPPLY CONNECTIONS.
CONDENSING UNIT
Top of slab should be located so run--off
10ACB TYPICAL FIELD WIRING DIAGRAM
ROOM THERMOSTAT
Y1
WG
C
Y1
C
TO 24V CLASS II POWER SOURCE
-- 20 VA MINIMUM
NOTE--IF INDOOR UNIT IS NOT EQUIPPED WITH
BLOWER RELAY, IT MUST BE FIELD PROVIDED
AND INSTALLED (P--8--3251 OR EQUIVALENT)
RC
WARNING
Unit must begrounded inaccordance with nation-
al and local codes. Electric Shock Hazard.
Can cause injury or death.
Line Voltage
To facilitate conduit, a hole is providedin bottom of the
control box. Connect conduit to hole in control box
with proper conduit fitting.
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WRUV RQO\
24V, Class II Circuit
24V, Class II Circuit connections are made upin thelow
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.
24V CLASS II INSTALLED AT FACTORY
24V CLASS II FIELD INSTALLED
RH
R
W1
G
W2
C
24V
CLASS II
JUNCTION
BOX
K3 INDOOR BLOWER RELAY
TYPICAL INDOOR UNIT
TO
HEATING
CONTROLS
COOLING
SPEED
TO
HEATING
SPEED
POWER
TRANSFORMER
24v
TO
T1
GROUND
PER NATIONAL
AND LOCAL
CODES
FIGURE 2
3DJH
PLUMBING
Field refrigerant piping consists of liquid and suction
lines from the condensing unit (sweat connections) to
the indoor evaporator coil (flare or sweatconnections).
Use Lennox L10 (flare) or L15 (sweat, non-flare) series
line sets as shown in table 1 or use field-fabricated re-
frigerant lines. Referto 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 jointswith a wetcloth to preventpossible
heat damage to the valve core an d opening port.
4-- A field provided filter drier should be installed as
close as possible to the expansion device.
REFRIGERANT METERING DEVICE
10ACBunits are applicableto either RFCIV oran 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. Table1 lists 10ACBunit liquid and suction
line sizes and corresponding line sets.
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.
TABLE 1
REFRIGERANT LINE KITS
UNIT
10ACB18
10ACB24
10ACB30
10ACB36
10ACB42
10ACB48
10ACB60
10ACB62
*Use reducer supplied in bag assembly.
LIQUID
LINE
5/16 in*
(8 mm)
3/8
(10 mm)
3/8 in
(10 mm)
3/8 in
(10 mm)
in
SUCTION
LINE
5/8 in
(16 mm)
3/4 in.
(19 mm)
7/8 in.
(22 mm)
1--1/8 in.
(29 mm)
LINE SETS
L10--21
20 ft. -- 50 ft.
(6m--15m)
L10--41
20 ft. -- 50 ft.
(6m--15m)
L10--65
30 ft. -- 50 ft.
(9m--15m)
FABRICATED
L10
FIELD
L15
LINE SETS
L15--21
20 ft. -- 50 ft.
(6m--15m)
L15--41
20 ft. -- 50 ft.
(6m--15m)
L15--65
30 ft. -- 50 ft.
(9m--15m)
FIELD
FABRICATED
3DJH
RF
DISTRIBUTOR
BULLET
ORIFICE
CIV INSTALLATION
ORIFICE
BODY
SEAL
NUT
FIGURE 3
SWEAT
CONNECTION
Expansion Valve Systems
Expansion valves equipped with either Chatleff or
flare type fittings are available from Lennox. Refer to
the indoor coil installation instructions ortheengineer-
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 wheninstalling an expan-
sion valveto the indoor coil will result in improper
operation and damage to the system.
0$1,)2/' *$8*( 6(7
A manifold gauge set equipped with low loss hoses
should be used when checking unit charge. A manifold
gauge set with anything other than low loss hose
should not be used.
/,48,' 68&7,21 /,1( 6(59,&( 9$/9(6
The liquid lineand 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.
T ighten 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.
'$1*(5
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.
3-- Replace stem cap tighten firmly. Tighten finger tight,
then tighten an additional 1/6 turn.
LIQUID LINE SERVICE VALVE (VALVE OPEN)
INSERT HEX
WRENCH HERE
SERVICE
PORT
TO OUTDOOR
COIL
SERVICE
PORT
CAP
SCHRADER
VALVE
LIQUID LINE SERVICE VALVE (VALVE CLOSED)
RETAINING RING
SERVICE
PORT
TO OUTDOOR
COIL
SERVICE
PORT CAP
SCHRADER VALVE OPEN
TO LINE SET WHEN VALVE
IS CLOSED (FRONT SEATED)
(VALVE FRONT SEATED)
FIGURE 4
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 seatthe valve. Tighten
firmly.
STEM CAP
TO INDOOR
COIL
STEM CAP
INSERT HEX
WRENCH HERE
TO INDOOR
COIL
3DJH
3-- Replace stem cap. Tighten finger tight, then tighten
an additional 1/6 turn.
SUCTION LINE SERVICE VALVE (VALVE OPEN)
INSERT HEX
WRENCH HERE
STEM CAP
SUCTION LINE (BALL TYPE) SERVICE VALVE
(VALVE OPEN)
USE ADJUSTABLE WRENCH
ROTATE STEM CLOCKWISE 90ETO CLOSE
ROTATE STEM COUNTER-CLOCKWISE 90ETO OPEN
STEM CAP
TO OUTDOOR COIL
TO INDOOR
COIL
SCHRADER
VALVE
SERVICE PORT
CAP
SERVICE PORT
TO OUTDOOR
COIL
SUCTION LINE SERVICE VALVE (VALVE CLOSED)
TO INDOOR
COIL
SERVICE
PORT
SERVICE PORT
CAP
SCHRADER VALVE OPEN
TO LINE SET WHEN VALVE IS
CLOSED (FRONT SEATED)
RETAINING RING
WRENCH HERE
(VALVE FRONT
STEM CAP
INSERT HEX
SEATED)
TO OUTDOOR
COIL
FIGURE 5
5
--Ton Suction Line (Ball Type) Service Valve
A ball-ty pe full service valve only is used on five ton units
(10ACB60/62 ). These suction lin e service valves function
the same way ,differences are in construction. Valves are
not rebuildable. If a valve has fail ed it must be re-
placed. A ball valv e valve is illustrated in figure 6.
The ball valve is equipped with a servi ce po rt. A
schrader valveis fac tory installed. A service po rt cap
is supplied to protect the sc hra der valve f rom con-
tamination and assure a leak free seal.
STEM
SERVICE PORT
CAP
SERVICE PORT
SCHRADER VALVE
BALL
(SHOWN OPEN)
TO INDOOR COIL
FIGURE 6
/($. 7(67,1*
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
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-22to 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.
amount is a maximum of 2 ounces or 3 poun
pressure.)
and the valveon the high pressure side of theman-
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.
Close the valve on the HCFC-22 bottle
for
2
(A trace
ds
3DJH
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 refrigerantadded 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 anygas 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 st art vacuum
pump.
4-- Evacuate the lineset and indoorunit to an
pressure
inch of mercury. During the early stages ofevacua-
tion, it is desirable to close the manifold gauge
valve at least once to determine if there is a rapid
rise in
indicates a relatively large leak. If this occurs, the
leak testing procedure must be repeated.
NOTE -- The term
of 23mm of mercury or approximately 1
absolute pressure
absolute pressure
. A rapid rise in pressure
absolute
means the to-
tal actual pressure within a given volume or sys-
tem, above theabsolute zero of pressure. Absolute
pressure in a vacuum is equal to atmospheric pres-
sure minus vacuum pressure.
5-- When the absolute pressure reaches 23mm ofmer-
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.
&$87,21
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 cylinderand 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 theabsolute pressure requirement abovehas
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.
3DJH
67$5783
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 thesys-
tem.
4-- Replace stem caps and secure finger tight, then
tighten an additional (1
5-- Check voltagesupply 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.
/6) one-sixth of a turn.
TABLE 3
Liquid Line
Set Diameter
5/16 in.
(8mm)
3/8 in.
(10mm)
*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.
Ozs. per 5 ft. (ml per mm) adjust
from 20 ft. (6.1m) line set*
2 ounce per 5 ft.
(57ml per 1.5m)
3 ounce per 5 ft.
(85ml per 1.5m)
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.
unit is charged depends on the units
tering
For RFC systems,
device
and the
outdoor ambient temperature
weighing in the charge
The way the
refrigerant me-
and
subcooling
are two acceptable means of charging under certain
conditions. For installations of an RFC system where the
outdoor ambient is less than 65EF(18EC), weighing in the
charge is the best method. However , in installations
where the outdoor ambient is 65EF(18EC) or above, sub-
cooling is the best method.
Weighing in the charge
and the
approach
method are
the two recommended procedures for charging the
10ACBusing an expansionvalve system forrefrigerant
metering. The difference between the two involves the
outdoor ambient temperature. For expansion valve
systems where the outdoor ambient temperature is
60EF(16EC) or above, the approach method may be
used. For expansion valve systems where the outdoor
ambient temperature is below 60EF(16EC),weighing in
the charge is recommended.
.
3DJH
TABLE 4
ENTERING
NORMAL OPERATI NG PRESSURES IN PSIG (LIQUID AND SUCTION +/-- 10 PSIG)*
OUT. COIL
ENTERING
MODE
AIR TEMP.
qF(q
65 (18.3) 145
75 (23.9) 167 77 181 70 188 70 197 68 203 66 185 72 182 72 180 71 188 68
85 (29.4) 192 81 208 75 216 74 227 73 233 70 210 73 204 73 210 74 219 72
RFCIV
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
85 (29.4) 189 81 209 77 217 75 228 75 235 72 217 74 205 73 202 76 211 73
TXV
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.
Use table 4 as a general guidefor 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.
10ACB12 10ACB18 10ACB24 10ACB30 10ACB36 10ACB42 10ACB48 10ACB60 10ACB62
LIQ. SUC. LIQ. SUC. LIQ. SUC. LIQ. SUC. LIQ. SUC. LIQ. SUC. LIQ. SUC. LIQ. SUC. LIQ. SUC.
C)
71 155 65 160 65 168 63 176 62 162 68 157 69 153 66 159 64
4 -- When thermostat demand has been satisfied,
IMPORTANT
switch to cooling mode with a set point of 68EF
(20EC). 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.
&+$5*,1* )25 5)& 6<67(06
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 forproperly 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.
Weighing in the Charge Method
RFC Systems, < 65EF
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 units rating plate.
The Subcooling Method
RFC Systems, >
1-- With the manifold gauge hosestill on the liquidser-
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,
determinethe saturation temperature forthe liquid
line pressure reading.
3DJH
65EF
(18EC)
(18EC)
Outdoor Temp
Outdoor Temp
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.
EF(E
C)
60
(16)
65
(18)
70
(21)
75
(24)
80
(27)
85
(29)
90
(32)
95
(35)
100
(38)
105
(41)
110
(43)
115
(45)
Note -- For best results, the same electronic thermometer should be
used to check both outdoor ambient and liquid temperatures.
LIQUID SUBCOOLING [+ 1EF (.6EC)]
012 018 024 030 036 042 048 060
14
(7.8)17(9.5)18(10)18(10)14(8)14(8)12(6.7)14(8)
13
(7.2)16(8.9)16(8.9)17(9.5)13(7.8)13(7.8)11(6.1)14(8)
12
(6.7)15(8.3)14(7.8)16(8.9)12(6.7)13(7.8)10(5.6)13(7.8)
10
(5.6)14(7.8)12(6.7)15(8.3)10(5.6)12(6.7)9(5)13(7.8)
9
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Weighing in the Charge
TXV Systems, < 60EF
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 units rating plate.
(16EC)
Outdoor Temp
The Approach Method
TXV Systems, >
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.
door AmbientEF(EC) = Approach Temperature.)
resulting difference (Approach temperature) should
60EF
(16EC)
Outdoor Temp
(Liquid LineEF(EC) -- Out-
The
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
EF(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.
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Condensing unit and indoor blower cycle on demand
from room thermostat. When thermostat blower
switch is switched toONposition, indoor blower oper-
ates continuously.
Crankcase Heater
Three and one-half, four and five ton units areequipped
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 thevalve 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
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blocked or dirty coil. The low pressure switch (SPST,
NO) protects thesystemcompressor fromdamage due
to loss of charge. The switch will trip at 15 +/-- 5 psig
(103 +/-- 34kPa) and automatically resets at 25 +/--3 psig
(172 +/-- 21 kPa).
Refrigerant Sight Glass (Option Units ONLY)
A refrigerant sight glass is provided in the bag assem-
bly for field installation. The sight glass can beinstalled
in the liquid line to help monitor system charge.
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At the beginning of each cooling season, the system
should be checked as follows:
1-- Clean and inspect condenser coil. Coil may be
flushed with a water hose. Make sure power is off
before cleaning.
2-- Visually inspect connecting lines and coils for evi-
dence of oil leaks.
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3-- Check wiring for loose connections.
4-- Check for correct voltage at unit (unit operating).
5-- Check condenser fan motor amp--draw.
Unit nameplate _________ Actual ____________ .
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Evaporator Coil
1-- Clean coil, if necessary.
2-- Check connecting lines and coils for evidence of oil
leaks.
3-- Check condensate 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 proce-
dure.
3--
Belt Drive Blowers --
tension.
4-- Check all wiring for loose connections
5-- Check for correct voltage at unit (blower operat-
ing).
6-- Check amp-draw on blower motor
Unit nameplate_________ Actual ____________.
Check belt forwear andproper
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