Evacuating and Charging the AC System
The primary use of a flushing kit is to remove contaminants from the AC system
hoses, evaporator, and condenser. Any other component of an AC system should
be bench checked or replaced, since flushing may be ineffective or may damage a
component. Flushing is usually performed after the recovery process. We
recommend it before you replace the compressor, or when you find contamination
in other components (receiver-drier, expansion valve, or connections). Some
recover/recycle machines have optional "flush kits." The only proper way to flush
system components is to use refrigerant in a closed-loop system.
Evacuating and Charging the AC System
Evacuate the system once the air conditioner components are repaired or
replacement parts are secured, and the AC system is reassembled. Evacuation
removes air and moisture from the system. Then, the AC system is ready for the
charging process, which adds new refrigerant to the system.
Evacuating the System
Follow this procedure:
1. Tighten all connections and attach a vacuum pump to the
center hose of the gauge set.
Figure 9-3
This illustration shows
evacuation of an AC system
before recharging. It is very
important to run the vacuum
pump long enough to insure
the removal of any moisture
that may be in the system.
2. Start the vacuum pump and open both the hand valves on the
manifold all the way. Run the pump for five minutes, then
close the hand valves and shut off the pump.
3. Check the gauge readings for five minutes. If the gauge
needles move up, the system is not sealed. There is a leak. Air
and moisture are being sucked into the system by the vacuum.
4. Tighten any loose connections. Re-start the pump, and open
the hand valves on the gauges again. Repeat the vacuum test.
