Leak Testing (Nitrogen Or Nitrogen-Traced); System Evacuation; Deep Vacuum Method (Recommended) - Daikin APGM3 Service And Troubleshooting

SERVICING
Using dry nitrogen, pressurize the system to 450 PSIG.
Allow the pressure to stabilize and hold for 15 minutes
(minimum). If the pressure does not drop below 450 PSIG,
the system is considered leak free. Proceed to system
evacuation using the Deep Vacuum Method. If after 15
minutes the pressure drops below 450 PSIG, follow the
procedure outlined below to identify system leaks. Repeat
the Standing Pressure Test.

Leak Testing (nitrogen or nitrogen-traced)

To avoid the risk of fire or explosion, never use oxygen,
high pressure air or flammable gases for leak testing of a
refrigeration system.
To avoid possible explosion, the line from the nitrogen
cylinder must include a pressure regulator and a pressure
relief valve. The pressure relief valve must be set to open at
no more than 450 PSIG.
Leak test the system using dry nitrogen and soapy
water to identify leaks. If you prefer to use an electronic
leak detector, charge the system to 10 PSIG with the
appropriate system refrigerant (See Serial Data Plate
for refrigerant identification). Using dry nitrogen, finish
charging the system to 450 PSIG. Apply the leak detector
to all suspect areas. When leaks are discovered, repair
the leaks, and repeat the pressure test. If leaks have been
eliminated proceed to system evacuation.

System Evacuation

Condensing unit liquid and suction valves are closed to
contain the charge within the unit. The unit is shipped with
the valve stems closed and caps installed. Do not open
valves until the system is evacuated.
REFRIGERANT UNDER PRESSURE!
Failure to follow proper procedures may cause property
damage, personal injury or death.
NOTE: Scroll compressors should never be used
to evacuate or pump down a heat pump or air
conditioning system.
WARNING
WARNING
WARNING
Prolonged operation at suction pressures less than 20
PSIG for more than 5 seconds will result in overheating of
the scrolls and permanent damage to the scroll tips, drive
bearings and internal seal.
LOW SIDE
GAUGE
AND VALVE
Evacuation

Deep Vacuum Method (Recommended)

The Deep Vacuum Method requires a vacuum pump
rated for 500 microns or less. This method is an effective
and efficient way of assuring the system is free of non-
condensable air and moisture. As an alternative, the Triple
Evacuation Method is detailed in the Service Manual for
this product model.
It is recommended to remove the Schrader Cores from the
service valves using a core-removal tool to expedite the
evacuation procedure.
1. Connect the vacuum pump, micron gauge, and
vacuum rated hoses to both service valves.
Evacuation must use both service valves to eliminate
system mechanical seals.
2. Evacuate the system to less than 500 microns.
3. Isolate the pump from the system and hold vacuum
for 10 minutes (minimum). Typically, pressure will rise
slowly during this period. If the pressure rises to less
than 1000 microns and remains steady, the system is
considered leak-free; proceed to system charging and
startup.
4. If pressure rises above 1000 microns but holds steady
below 2000 microns, non-condensable air or moisture
may remain or small leak is present. Return to step
2: If the same result is achieved, check for leaks and
repair. Repeat the evacuation procedure.
CAUTION
HIGH SIDE
GAUGE
AND VALVE
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