MDV CCA3U-09HRFN1-MC, Service Manual, Page: 93 / 213

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2.2 Power on and let the air conditioner
operate for cooling. Check operation status
of drainage pump, and then connect the
plug of water level switch, check the
operation sound of water pump and
observe whether the water can discharge
through the transparent hard pipe at
drainage outlet. (In light of the length of
drainage pipe, water shall be discharged
about 1 minute delayed)
2.3 Stop the operation of air conditioner, power
off the power supply and put the cover of
water test hole back to the original place.
a. After stopped the air conditioner 3 minutes,
check whether there is anything abnormal.
If drainage pipes have not been distributed
properly, over back-flow water shall cause
the flashing of alarm indicator at
remote-controlled receiving board and
even water shall run over the water
collector.
b. Continuously infusing water until water
level alarmed, check whether the drainage
pump could discharge water at once. If
water level does not decline under warning
water level 3 minutes later, it shall cause
shutdown of unit. When this situation
happens, the normal startup only can be
recovered by turning down power supply
and eliminating accumulated water.
Note: Drain plug at the main water-containing
plate is used for eliminating accumulated water
in water-containing plate when maintaining air
conditioner fault. During normal operation, the
plug shall be filled in to prevent leakage.
12.5.4 Insulation work of drainage pipe
Refer the introduction to the insulation
engineering parts.
Vacuum Drying and Leakage Checking
12.6.1 Purpose of vacuum drying

Eliminating moisture in system to prevent
the phenomena of ice-blockage and copper
oxidation.
Ice-blockage shall cause abnormal
operation of system, while copper oxide
shall damage compressor.

Eliminating the non-condensable gas (air)
in system to prevent the components
oxidizing, pressure fluctuation and bad heat
exchange during the operation of system.
12.6.2 Selection of vacuum pump

The ultimate vacuum degree of vacuum
pump shall be -756mmHg or above.

Precision of vacuum pump shall reach
0.02mmHg or above.
12.6.3 Operation procedure for vacuum
drying
Due to different construction environment, two
kinds of vacuum drying ways could be chosen,