Mitsubishi Electric ECOV-X37VA Manuel D'installation page 17

4. Precautions for installation
4-1. Precautions for installing the unit
•Protect and maintain the pipes to prevent infiltration of contaminants such as water and dirt.
•Nitrogen purge is required to prevent formation of oxide scale while brazing the pipes.
The unit contains a scroll compressor. The usage of this unit is different from that of a unit containing a reciprocating com-
pressor. Improper use may cause damage to the compressor. Read carefully and follow the directions below.
[1] Use R744 refrigerant.
The design pressure on the high-pressure side is 12 MPa, and that on the low-pressure side is 8 MPa. (Refer to "4-2-1.Re-
frigerant pipes".)
Only use the refrigerant that is specified by Mitsubishi Electric.
[2] Entire compressor is hot.
The entire compressor is hot during operation and immediately after stoppage. Wait for the pressure and temperature inside
the compressor to drop, especially before conducting a test run, maintenance, or servicing.
[3] Use ester oil as refrigerant oil.
Ester oil is used for this unit. Ester oil easily absorbs moisture and tends to cause deterioration of the refrigerant oil or for-
mation of sludge (hydrate). Therefore, complete vacuum drying is required.
Ensure to follow the basic requirements and precautions for piping work to prevent infiltration of water or dirt.
[4] Do not change the wiring connection on
the secondary side.
Do not change the phase of the wiring between the Invert-
er board and the compressor.
Do not change the phase at the compressor terminal
block.
[5] Vacuum drying without specified tools is prohibited.
Vacuum drying must be performed by a specialist. Do not force the unit to operate with the refrigerant service valve (ball
valve) <suction> closed. Refer to the relevant pages for the vacuum drying procedures. (Page 32)
[6] Forced stop of the evaporator fan is prohibited.
Do not operate the unit with the evaporator fan stopped (except for the short period of time immediately after defrosting).
Close the solenoid valve <liquid> and pump down-stop the unit before stopping the evaporator fan.
[7] Closing the refrigerant service valve <suction> during operation is prohibited.
Pump down operation, which causes a sudden decrease in the low pressure (for example, by closing the refrigerant service
valve (ball valve) <suction> during operation) may cause the refrigerant to foam, resulting in migration of a large amount of
refrigerant oil out of the compressor and damage to the compressor.
Spend at least 30 seconds decreasing the pressure, for example, from 1.2 MPa to 1.0 MPa.
Inverter board
Secondary wiring
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WT09614X03_GB