To Triple Evacuate or Deep Vacuum . . .

By: Peter Kirtschej, Service Advisor, ABR Wholesalers, Inc.

To triple evacuate or deep vacuum - that is the question.  Either way, you will achieve your goal.

The process for triple evacuation is fairly straightforward:

  1. Connect the gauges to the condenser.
  2. Connect the yellow hose from the gauge set to the evacuation pump.
  3. Open the valves on the gauges and start the pump.
  4. Pull a vacuum to -30 inches of mercury and run the pump for 15 minutes.
  5. Close the valves on the gauge set then turn off the pump.
  6. Connect the yellow hose to the nitrogen tank and let nitrogen into the system until it reaches 2 psi on the gauge set.
  7. Close the gauges and let the system sit for an hour.  Why so long?  Doing this will give the nitrogen time to absorb the moisture in the system.
  8. Hook the pump in line with the gauge set and micron gauge.
  9. Open the valves on the gauge set and turn on the pump.
  10. Run the pump until you have reached 500 microns.
  11. Close the valves on the gauge set and add nitrogen to the system again until the meter reads 2 psi.  Let the system sit for an additional hour.
  12. Evacuate the system a final time until you have achieved 250 microns.  Note:  some manufacturers recommend 500 microns - I prefer 250.

To run a deep vacuum:

  1. Connect the gauge set to the service ports on the condenser.
  2. Connect the micron gauge to either the port on the vacuum pump or in line with one of the hoses between the condenser and manifold.
  3. Run the pump until it reaches 500 microns (Check with the manufacturer - some recommend 250 microns).
  4. Valve off the gauges and turn off the pump - make sure you are isolating the refrigeration system from the vacuum pump because it is possible for the vacuum in the system to pull the oil out of the pump and into the system.
  5. Now watch the micron gauge ...
    1. If the reading has not moved, the moisture has been successfully removed from the system.
    2. If the gauge starts to slowly rise, there is either moisture in the system or a very small leak.  If the gauge rises quickly, then there is a leak that needs to be addressed before continuing evacuation.

Regardless of the method you choose, both processes will end the same - moisture and non-condensables will be removed from the refrigeration system, thereby protecting the system and preventing txv valve failures.

For more information, contact ABR today.