Compressor Replacement Instructions (Only P450-P650 Types) - Mitsubishi Electric PURY-P200 Service Handbook

[6] Compressor Replacement Instructions (only P450-P650 types)

Follow the instructions below when replacing the compressor.
When replacing the compressor No.1 (inverter drive), start replacing after judging whether the compressor is
malfunctioning or the inverter is malfunctioning. When only one compressor is malfunctioning, operate the
compressor for approximately an hour under emergency operation mode before the replacement, check the items
below, and replace the compressor after examining whether the return oil circuit is working properly or not.
Refer to the right chart for the temperature of each part.
< When normal >
1 Temperature of A = Temperature of C, and
Temperature of A > Outdoor temperature + 10deg
2 Temperature of B = Temperature of C, and
Temperature of B > Outdoor temperature + 10deg
< When abnormal >
When 1 is abnormal (out of range)
Return oil failure due to SV1 circuit failure
When 2 is abnormal (out of range)
Return oil failure due to capillary blockage
(1) Make sure that the main power is OFF.
When replacing the compressor due to megger fault and the megger is
to the liquified refrigerant gas entering and accumulating in the compressor. Turn the power off after powering
the crankcase heater at least 12 hours, and apply megger again.
(2) Remove the fin guard, the front panel and the front partition plate on the right (as you face the front).
(3) Drain the refrigerant from the check joint for high and low pressure service.
When collecting refrigerant from the accumulator, perform proper work with the reference of the liquid
refrigerant collecting method from the accumulator.
(4) Drain the refrigerating machine oil from the drain oil pipe that is located on the equal oil pipe.
Note : When draining the oil, prepare an approximately 10-liter container.
Note : Keep draining oil until the oil in the drain oil plug clears up.
Note : Keep track of the amount of drained oil, as the same amount of oil will be added.
Note : Do not splash oil.
Note : Do not leave the refrigerant circuit open for a long time, as the oil rapidly absorbs moisture.
Note : The drained oil cannot be recycled.
(5) After draining oil from the refrigerant and the drain oil plug, remove the metal fitting-1 or the flare nuts
(2 places) that connect the compressor and the equal oil pipe, and bend the equal oil pipe so as not to apply
an excess force.
(6) Close the equal oil pipe attachment point with a cap to prevent the oil from leaking.
(7) Remove the compressor terminal cover, and remove the power supply wiring.
(8) Remove the sound-proof material that is winded around the discharge temperature thermistor and the compressor.
(9) Remove the crankcase heater.
(10) Heat the brazing part of the discharge pipe and the suction pipe, and remove the pipes.
(11) Remove the compressor fixing nut and the metal fitting-2 (3 places for compressor-2).
(12) Replace the compressor with the service compressor.
(13) Braze the discharge pipe and the suction pipe.
(14) Attach the equal oil pipe to both compressors. Replace the dryer with the new one. After replacing the dryer,
do not leave the refrigerant circuit open for long time.
Note : When replacing the compressor and when the equal oil pipe is damaged or irreparably deformed,
after replacing the compressor, heat the junction of the equal oil pipe, remove the equal oil pipe,
and braze the service equal oil pipe.
(15) Close the ball valves in the outdoor unit (both on the high pressure and the low pressure side), and
pressurize up to 4.15MPa with nitrogen from the check joint for high and low pressure service.
(16) After confirming the airtightness, emit nitrogen gas.
(17) Open the ball valves in the outdoor unit (both on the high pressure and the low pressure side), and perform
vacuuming.
(18) While vacuuming, add the same amount of oil that is drained from the drain oil plug on the equal oil pipe in
the procedure (4).
Note : The oil to be added must be MEL32 made by Nisseki Mitsubishi. When adding oil, the oil must not
absorb moisture, and do not use the oil that is over a year old.
Note : Do not drain the oil in the compressor and return the oil, as it will be used to examine for reasons
for the compressor malfunction.
Compressor
→
Replace SV1 circuit.
→
Replace the capillary
- 191 -
Four-way/Valve
SV1 A
C
Oil
sepa-
B
rator
Capillary
1Ω or more, megger drop is likely due