18
UNIT DAMAGE AND ENVIRONMENTAL HAZARD
Failure to follow this caution may result in unit damage.
When evaluating the refrigerant charge, an
indicated adjustment to the specified factory
charge must always be very minimal. If a
substantial adjustment is indicated, an abnormal
condition exists somewhere in the cooling
system, such as insufficient airflow across either
coil or both coils. Always recover refrigerant,
never vent to the atmosphere.
!
CAUTION
Proceed as follows:
1. Remove cap from low--pressure service fittings.
2. Using hoses with valve core depressors, attach
low--pressure gauge hose to low--pressure service
fitting.
3. Start unit in Cooling Mode and let unit run until system
pressures stabilize.
4. Measure and record the following:
a.
Outdoor ambient--air temperature (
°
F(
°
C)db).
b.
Suction line temperature (
°
F(
°
C)).
c.
Suction (low--side) pressure (psig).
5. Using “Cooling Charging Charts,” compare outdoor--air
temperature(
°
F (
°
C) db) with the suction line pressure
(psig) to determine desired system operating suction
line temperature (See Table 5).
6. Compare actual suction line temperature with desired
suction line temperature. Using a tolerance of +/-- 3
°
F
(1.7
°
C), add refrigerant if actual temperature is higher
than proper suction line temperature, or remove
refrigerant if actual temperature is lower than required
suction line temperature.
NOTE
: If the problem causing the inaccurate readings is a
refrigerant leak, refer to the Check for Refrigerant Leaks
section.
Table 4—
Cooling Charging Chart
