Mitsubishi Electric PURY-HP144, Service Handbook

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[1-3 Working with Refrigerant Piping ]
10 -
chapter 1 HWE18220_GB
1 Check Before Servicing
7. Triple Evacuation
The method below can also be used to evacuate the system.
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Evacuate the system to 4,000 microns from both service valves. System manifold gauges must not be used to measure vac-
uum. A micron gauge must be used at all times. Break the vacuum with Nitrogen (N2) into the discharge service valve to 0
PSIG.
Œ
Evacuate the system to 1,500 microns from the suction service valve. Break the vacuum with Nitrogen (N2) into the discharge
service valve to 0 PSIG.
Œ
Evacuate the system to 500 microns. System must hold the vacuum at 500 microns for a minimum of 1 hour.
Œ
Conduct a rise test for a minimum of 30 minutes
8. Notes
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To evacuate air from the entire system
Applying a vacuum through the check joints at the refrigerant service valve on the high and low pressure sides (BV1
and 2) is not enough to attain the desired vacuum pressure.
Be sure to apply a vacuum through the check joints at the refrigerant service valve on the high and low pressure
sides (BV1 and 2) and also through the check joints on the high and low pressure sides (CJ1 and 2).
Œ
To evacuate air only from the outdoor units
Apply a vacuum through the check joints on the high and low pressure sides (CJ1, and 2).
Œ
To evacuate air from the indoor units and extension pipes
Apply a vacuum through the check joints at the refrigerant service valve on the high and low pressure sides (BV1
and 2).