Midea ATOM B Series Service Manual page 84

2.23.11 Compressor replacement procedure
Step 1: Remove faulty compressor and remove oil
 Remove the faulty compressor from the outdoor unit.
 Before removing the oil, shake the compressor so as to not allow impurities to remain settled at the bottom.
 Drain the oil out of the compressor and retain it for inspection. Normally the oil can be drained out from the compressor
discharge pipe.
Step 2: Inspect oil from faulty compressor
 The oil should be clear and transparent. Slightly yellow oil is not an indication of any problems. However, if the oil is
dark, black or contains impurities, the system has problems and the oil needs to be changed. Refer to Figure 6-2.7 for
further details regarding inspecting compressor oil. (If the compressor oil has been spoiled, the compressor will not be
being lubricated effectively. The scroll plate, crankshaft and bearings will wear. Abrasion will lead to a larger load and
higher current. More electric energy will get dissipated as heat and the temperature of the motor will become
increasingly high. Finally, compressor damage or burnout will result.)
Step 3: Check oil in other compressors in the system
 If the oil drained from the faulty compressor is clean, go to Step 6.
 If the oil drained from the faulty compressor is spoiled (lightly or heavily), go to Step 4.
Step 4: Replace oil separator and accumulator
 If the oil from a compressor is spoiled (lightly or heavily), drain the oil from the oil separator and accumulator in that
unit and then replace them.
Step 5: Check filters(s)
 If the oil from a compressor is spoiled (lightly or heavily), check the filter between the gas stop valve and the 4-way
valve in that unit. If it is blocked, clean with nitrogen or replace.
Step 6: Replace the faulty compressor and re-fit the other compressors
 Replace the faulty compressor.
 If the oil had been spoiled and was drained from the non-faulty compressor
in Step 3, use clean oil to clean them before re-fitting it into the unit. To clean,
add oil into the compressor through the discharge pipe using a funnel, shake
the compressor, and then drain the oil. Repeat several times and then re-fit
the compressors into the units. (The discharge pipe is connected to the oil
pool of the compressor by the inner oil balance pipe.)
Step 7: Add compressor oil
 Add oil to each of the compressors from which oil was drained in Step 3.
 Only use RB75EA oil. Different compressors require different types of oil.
Using the wrong type of oil leads to various problems.
 Add oil to the accumulator from which oil was drained in Step 4.
Step 8: Vacuum drying and refrigerant charging
 Once all the compressors and other components have been fully connected, vacuum dry the system and recharge
refrigerant.
Atom B Series VRF 50/60Hz
Figure 6-2.6: Compressor piping
Discharge pipe
Suction pipe
83