After Leak Test, relieve all the pressure in the
system. If only Nitrogen was used evacuate into
the air by removing the stem valve from the
connection port. If you have not installed a stem
valve, disconnect the hose carefully. High
pressure Nitrogen is in the system and will
forcefully evacuate, posing a danger to the
installer (an impact of flying hose at such high
pressure can cause injury)
If the Low Pressure method was used, recover
the refrigerant with vacuum pump. Allow time
for the recovery process (20 minutes per ton) to
complete. The vacuum scale should be up to 30
HG negative pressure at sea level.
When ready to Power the system on for the first
time, the installer must charge the system with
refrigerant.
The Low Pressure Switch may have to be
bypassed for this process as the compressor will
most likely be shut down due to low pressure.
The Thermostat will also need to be bypassed
for the unit to maintain functioning until the
charging process is complete. When charging
the unit, the installer will meter refrigerant, check
electrical characteristics, measure air
