5-11. REFRIGERANT PRESSURE
This task covers:
Tool kit, refrigeration SVC
Voltages used can kill. Always disconnect power
cord to air conditioner before performing any
internal maintenance. Shutting unit off at its
control panel does not disconnect unit power.
Except in cases where it is obvious that the refrigerant charge has been lost, the first step in troubleshooting
problems in the refrigeration system should be to check discharge and suction pressures under operating conditions. Check
pressures as follows.
a. Turn the mode selector switch to OFF.
b. Remove protective caps from charging valves.
c. Connect individual pressure gages, or a refrigeration charging manifold and hoses to the high (discharge) and low
(suction) charging valves.
Take care that only a very small amount of refrigerant is allowed to escape during hose purging.
d. Loosen hose connections at gages or charging manifold.
e. Open high (discharge) pressure manifold valve slightly to purge air from hose. Tighten low pressure hose connection
at gage fitting as soon as a hissing sound is heard.
f. Open low (suction) pressure manifold valve slightly to purge air from hose. Tighten low pressure hose connection at
gage fitting as soon as a hissing sound is heard.
g. Open the low (suction) and high (discharge) manifold valves.