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.
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 (35 kPa) without contaminating the system.
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