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IMPORTANT
The compressor should never be used to evacu-
ate a refrigeration or air conditioning system.
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
testing section would be necessary.
3− After system has been evacuated to 29 inches
(737mm), close gauge manifold valves to center port,
stop vacuum pump and disconnect from gauge man-
ifold. Attach an upright nitrogen drum to center port of
gauge manifold and open drum valve slightly to purge
line at manifold. Break vacuum in system with nitro-
gen 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
slightly with refrigerant to break vacuum.
D − Charging
Charging must be done in the cooling mode. If the sys-
tem is completely void of refrigerant, the recommended
and most accurate method of charging is to weigh the re-
frigerant into the unit according to the total amount shown on
the unit nameplate. Also refer to the SPECIFICATIONS tables
on pages 1 and 2.
If weighing facilities are not available or if unit is just low on
charge, the following procedure applies.
IMPORTANT
The following procedures require accurate
readings of ambient (outdoor) temperature, liquid
temperature and liquid pressure for proper
charging. Use a thermometer with accuracy of
+2°F( + 1.1°C) and a pressure gauge with accuracy
of +5PSIG ( + 34.5kPa).
For best results, indoor temperature should be between
70°F and 80°F (21°C and 27°C) . If outdoor temperature is
60°F (16°C) or above the approach method of charging is
used. If outdoor temperature is less than 60°F (16°C) the
subcooling method of charging is used. Slight variations in
charging temperature and pressure should be expected.
Large variations may indicate a need for further servic-
ing.
APPROACH METHOD (TXV SYSTEMS)
(Ambient Temperature of 60_F [16_C] or Above)
1 − Connect gauge manifold. Connect an upright R−22
drum to center port of gauge manifold.
2 − Record outdoor air (ambient) temperature.
3 − Operate indoor and outdoor units in cooling mode. Al-
low outdoor unit' to run until system pressures stabi-
lize.
4 − Make sure thermometer well is filled with mineral oil
before checking liquid line temperature.
5 − Place thermometer in well and read liquid line tem-
perature. Liquid line temperature should be warmer
than the outdoor air temperature. Table 6 shows how
many degrees warmer the liquid line temperature
should be.
Add refrigerant to lower liquid line temperature.
Recover refrigerant to raise the liquid line tem-
perature.
Add refrigerant slowly as the unit approaches the
correct temperature. This will allow refrigerant to sta-
bilize allowing the correct temperature to be read.
APPROACH METHOD
AMBIENT TEMPERATURE OF 60 _F (16 _C) OR ABOVE
Model
12HPB24
12HPB30
12HPB36
12HPB42
12HPB48
12HPB60
Page 12
TABLE 6
LIQUID LINE_F − OUTDOOR AMBIENT_F
6°F (3.3°C)
11°F (6.1°C)
12°F (6.7°C)
10°F (5.6°C)
9°F (5.0°C)
8°F (4.4°C)
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