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NOTE:
Two pumps will speed up the procedure. One (1) vacuum pump
located normally outside at the condenser or condensing unit and one (1)
vacuum pump is located indoors at the evaporator unit.
The vacuum pump should be connected to the discharge line after the check valve and the liquid
line before the metering device via vacuum rated hoses and Schrader valve core removal tools.
On the high side of the system there is a Schrader port located on the leaving side of the check
valve and on the liquid line before the expansion valve, attach your Schrader valve core removal
tools and hoses here. A micron gauge should be fitted to the system at the furthest point from
the vacuum pump. Install a Schrader valve core removal tool with shutoff valve before the
micron gauge to prevent damage to the micron gauge during charging.
5.1.2. First Stage Evacuation
1. With the refrigerant valves fully open, open the Schrader core shutoff valve and evacuate
the refrigerant lines, condenser coil and evaporator coil (the complete refrigerant system)
from both, low and high sides of the system to 2000 microns or less.
2. Close the Schrader core shutoff valve and turn OFF the vacuum pump.
3. Disconnect the vacuum pump hoses from the vacuum and attached them to your manifold
gauges.
4. Connect a vacuum hose from the nitrogen bottle regulator to the manifold gauges vacuum
port and carefully break the vacuum with clean dry nitrogen. Slowly raise the pressure to
approximately 5 PSIG without contaminating the system.
5. Isolate and hold the nitrogen charge for at least one (20) minutes.
6. Verify no nitrogen leaks.
7. Carefully release the nitrogen charge. Watching the gauge until it reads 5 PSIG.
5.1.3. Second Stage Evacuation
1. Move the vacuum hoses back to the vacuum pump and restart the pump.
2. Open the Schrader core shutoff valve and evacuate the refrigerant system from both sides
of the system to 1500 micron or less.
3. Close the Schrader core shutoff valve and turn OFF the vacuum pump.
4. Disconnect the vacuum pump hoses from the vacuum and attached them to your manifold
gauges.
5. Connect a vacuum hose from the nitrogen bottle regulator to the manifold gauges vacuum
port and carefully break the vacuum with clean dry nitrogen. Slowly raise the pressure to
approximately 5 PSIG without contaminating the system.
6. Isolate and hold the nitrogen charge for at least one (10) minutes.
7. Verify no nitrogen leaks.