Checking Compressor Efficiency - Daikin M Series Service And Troubleshooting

SERVICING
NOTE: R410A should be drawn out of the storage
container or drum in liquid form due to its fractionation
properties, but should be "Flashed" to its gas state
before entering the system. There are commercially
available restriction devices that fit into the system
charging hose set to accomplish this. DO NOT charge
liquid R410A into the compressor.
4. With the system still running, close the valve on the
charging cylinder. At this time, you may still have
some liquid refrigerant in the charging cylinder hose
and will definitely have liquid in the liquid hose.
Slowly open the high side manifold valve and transfer
the liquid refrigerant from the liquid line hose and
charging cylinder hose into the suction service valve
port. CAREFUL: Watch so that liquid refrigerant
does not enter the compressor.
Due to their design, Scroll compressors are inherently more
tolerant of liquid refrigerant.
NOTE: Even though the compressor section of a
Scroll compressor is more tolerant of liquid refrigerant,
continued floodback or flooded start conditions may
wash oil from the bearing surfaces causing premature
bearing failure.

Checking Compressor Efficiency

The reason for compressor inefficiency is broken or
damaged suction and/or discharge valves, or scroll
flanks on Scroll compressors, reducing the ability of the
compressor to pump refrigerant vapor.
The condition of the valves or scroll flanks is checked in the
following manner:
1. Attach gauges to the high and low side of the
system.
2. Start the system and run a Cooling Performance
Test.
If the test shows:
A. Below normal high side pressure.
B. Above normal low side pressure.
C. Low temperature difference across coil.
D. Low amp draw at compressor.
-and the charge is correct. The compressor is faulty -
replace the compressor.
29