58
Evacuation
•
Carefully inspect pump and related equipment before connecting to system.
Ensuring gaskets are in good condition and pump is capable of low vacuum levels can
save time. Connect pump(s) to as many locations as possible ensuring all locations
are well sealed. If a field charge will be required, connecting a refrigerant tank to the
system with a good valve is recommended. Any hose connections requiring purging of
non-condensable can be done at this point.
•
Evacuate the line and remote condenser to 400 microns measured at a point on the
system furthest away from the pump.
-
Note that a gauge installed on the pump or in close proximity will give a lower
reading while the unit is being evacuated.
-
A deep vacuum gauge should be used to evaluate the pressure. Compound
manifold gauges do not allow for enough accuracy at the pressures required.
-
The system should be able to hold a vacuum under 500 microns for more
than
10
minutes.
-
If pressure continuously rises at a rapid rate there is likely a system leak.
Review all piping connections and correct before continuing evacuation.
-
Pressure rising above 500 microns and tending to stabilize at a higher
pressure indicates the system has moisture above specifications. Continue
evacuation until 500 microns or lower can be held for a minimum of 10
minutes.
Alternative Evacuation Specified by Process
After components have been repaired or replaced evacuation procedure should take place.
Very small amounts of refrigerant may still be mixed with the oil in the system. Out-gassing of
this refrigerant may interfere with the evacuation and vacuum decay testing.
IF, AND ONLY IF
, a unit has been previously charged with refrigerant, and standard
evacuation method has not been successful after 24 hours minimum using the standard
procedure, the following alternative method should be used.
1.
Check vacuum level. It should be a maximum of 1,500 microns absolute pressure.
If this is not the case, review system for leaks and continue evacuation process until
1,500 microns is achieved.
2.
Purge system with nitrogen to atmospheric pressure (0 gauge pressure).
Ensure all portions of systems are at this pressure. Seal system and wait 10 minutes.
Desert Aire - LC/LV Manual
Summary of Contents for ExpertAire LC Series
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