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V−CHARGING
Unit charge is based on a matching indoor coil and outdoor
coil with a 15 foot (4.5m) line set. For varying lengths of line
set, refer to table 8.
IMPORTANT
If line length is greater than 15 feet (4.5m), add
the amount of refrigerant listed in table 8 . If line
length is less than 15 feet (4.5), subtract this
amount.
Liquid Line
Set Diameter
3/8 in. (9.5 mm)
TABLE 8
Ounce per 5 foot (ml per mm) adjust from
15 ft. (4.5m)*
*If line set is greater than 15 ft. (4.5m) add this amount. If line set is less than
15 ft. (4.5m) subtract this amount
3 ounce per 5 feet (88.05g per 1.5m)
A−Leak Testing
1 − Attach gauge manifold and connect a drum of dry ni-
trogen to center port of gauge manifold.
2 − Add a small amount of refrigerant to the lines and coil.
Open high pressure gauge valve and pressurize line
set and indoor coil to 150 psig (1034 kPa).
WARNING
Danger of Explosion.
Can cause injury, death and equipment
damage.
When using dry nitrogen, use a pres-
sure−reducing regulator, set at 150 pig
(1034 kPa) or less to prevent excessive
pressure.
3 − Check lines and connections for leaks.
NOTE-If electronic leak detector is used, add a trace of re-
frigerant to nitrogen for detection by leak detector.
4 − Release nitrogen pressure from the system, correct
any leaks and recheck.
B−Evacuating the System
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 temperatures and
pressures present during operation of an air conditioning
system. Non−condensables such as water vapor, combine
with refrigerant to produce substances that corrode copper
piping and compressor parts.
CAUTION
Danger of Equipment Damage. Avoid deep vacu-
um operation. Do not use compressors to evacu-
ate a system. Extremely low vacuums can cause
internal arcing and compressor failure. Damage
caused by deep vacuum operation will void war-
ranty.
1− Attach gauge manifold. Connect vacuum pump (with
vacuum gauge) to center port of gauge manifold. With
both manifold service valves open, start pump and evac-
uate indoor coil and refrigerant lines.
IMPORTANT
A temperature vacuum gauge, mercury vacuum
(U−tube), or thermocouple gauge should be used.
The usual Bourdon tube gauges are not accurate
enough in the vacuum range.
2− Evacuate the system to 29 inches (737mm) vacuum.
During the early stages of evacuation, it is desirable to
stop the vacuum pump at least once to determine if there
is a rapid loss of vacuum. A rapid loss of vacuum would
indicate a leak in the system and a repeat of the leak test-
ing section would be necessary.
3− After evacuating system to 29 inches (737mm), close
gauge manifold valves to center port, stop vacuum pump
and disconnect from gauge manifold. Attach an upright
nitrogen drum to center port of gauge manifold and open
drum valve slightly to purge line at manifold. Break vacu-
um in system with nitrogen pressure by opening manifold
high pressure valve. Close manifold high pressure valve
to center port.
4− Close nitrogen drum valve and disconnect from
gauge manifold center port. Release nitrogen pres-
sure from system.
5− Connect vacuum pump to gauge manifold center
port. Evacuate system through manifold service
valves until vacuum in system does not rise above
.5mm of mercury absolute pressure or 500 microns
within a 20−minute period after stopping vacuum
pump.
6− After evacuation is complete, close manifold center port,
and connect refrigerant drum. Pressurize system slight-
ly with refrigerant to break vacuum.
C−Charging
Charging must be done in the cooling mode.If system is
completely 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. Length of refrigerant lines should be consid-
ered. See table 8 for varying line lengths.
If weighing facilities are not available or if unit is just low on
charge, the following procedure applies.
Separate discharge and vapor line service ports are pro-
vided outside the unit for connection of gauge manifold
during charging procedure as well as a suction line service
port.
