Mitsubishi Electric ECOV-X37VA Manuel D'installation page 33

[3] Vacuum drying procedure
Be sure to use a vacuum pump for vacuum drying of the system. Vacuum drying must be performed by a specialist.
The low pressure is digitally displayed on the Main board. Unless the unit is energized during the vacuum drying, the
low-pressure is not displayed on the Main board. Check the low-pressure by using a gauge manifold and a vacuum
gauge.
1. Connect to the vacuum pump.
For information on the vacuum pump connection, refer to the relevant pa
2. Evacuate the air from the check joint connected to the refrigerant service valve (three-way valve) <liquid> in
the high-pressure circuit.
Because a check valve is used in the low-pressure circuit, perform vacuum drying with the high-pressure cir-
cuit first (the capacity will be larger).
3. Evacuate the air from the check joint at the compressor inlet in the low-pressure circuit.
When performing vacuum drying, open the refrigerant service valve (three-way valve) <liquid> and the refrigerant
service valve (three-way valve) <injection> half way, and the ball valve <suction> all the way.
For how to open the refrigerant service valve (three-way valve) <liquid> and the refrigerant service valve (three-
way valve) <injection> half way, refer to section 8-2-6. (Page 35).
(The condensing unit is filled with nitrogen. Attempting vacuum drying without opening the valves as described
above will not eliminate air out of the condensing unit.)
4. When the vacuum drying is completed, close the check joint and remove the vacuum pump.
ge. (Page 34)
Refrigerant service valve (three-way valve)
<injection>
COMP inlet CJ
Liquid outlet CJ
Refrigerant service valve
(three-way valve) <liquid>
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