Section 22: HEATING AND AIR CONDITIONING
PA1562
17
6.5.1 Double Sweep Evacuation Procedure
1. Remove any remaining refrigerant from the
system using a refrigerant recovery
machine.
2. Connect the evacuation manifold, vacuum
pump, hoses and micron gauge to the unit.
3. With the unit service valves closed (back
seated) and the vacuum pump and the
thermistor valves open, start the pump and
draw the manifold and hoses into a very
deep vacuum. Shut the vacuum pump off
and see if the vacuum holds. This is to
check the setup for leaks.
4. Midseat the system service valves.
5. Open the vacuum pump and the thermistor
valves. Start the pump and evacuate to a
system pressure of 2000 microns.
6. Close the vacuum pump and the thermistor
valves, turn off the vacuum pump (closing
the thermistor valve protect the valve from
damage).
7. Break the vacuum with clean refrigerant (or
dry nitrogen) and raise the pressure to
approximately 2 PSIG. Monitor the pressure
with the compound gauge.
8. Remove the refrigerant with the recovery
machine.
9. Repeat steps #5 – 8 one time.
FIGURE 17: DOUBLE SWEEP EVACUATION SET-UP 22298
To Next Page
Loading...
