Mitsubishi Electric CITY MULTI PUMY-P NHMU Installation Manual page 12

nals.
After installation or after the power source to the unit has been cut for an extended
period, the insulation resistance will drop below 1 M due to refrigerant accumulating
in the compressor. This is not a malfunction. Perform the following procedures.
1. Remove the wires from the compressor and measure the insulation resistance of
the compressor.
2. If the insulation resistance is below 1 M , the compressor is faulty or the resist-
ance dropped due the accumulation of refrigerant in the compressor.
3. After connecting the wires to the compressor, the compressor will start to warm
up after power is supplied. After supplying power for the times indicated below,
Refer to the indoor unit installation manual.
unit operates properly following the installation manual attached to the unit.
erroneous connection, if any, of the refrigerant pipes and the connecting
wires.
* The compressor operation is not available for 3 minutes at least after the
power is supplied.
of low outside air temperature.
Once the compressor stops, the restart preventive device operates so the compressor
will not operate for 3 minutes to protect the air conditioner.
Perform the following procedures to collect the refrigerant when moving the indoor
unit or the outdoor unit.
1 Turn off the circuit breaker.
2 Connect the low pressure side of the gauge manifold to the service port of the
gas side stop valve.
3 Close the liquid stop valve.
4 Supply power (circuit breaker).
* Start-up of the indoor-outdoor communication takes about 3 minutes after the
power (circuit breaker) is turned on. Start the pump-down operation 3 to 4 minutes
5
run for cooling operation. The compressor (outdoor unit) and ventilators (indoor
and outdoor units) start operating and test run for cooling operation begins.
Immediately after performing the test run for cooling operation, set the outdoor
sure to switch it to OFF after pump down is completed.
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4. If the insulation resistance rises above 1 M , the compressor is not faulty.
.
- Starting operation immediately after turning on the main power switch can result
Note:
* After performing the test run, set SW3-1 to OFF.
6 Fully close the gas stop valve when the pressure reading on the gauge drops
7 Set SW3-1 to OFF to stop the air conditioner operation. (Set the outdoor service
8 Turn off the power supply (circuit breaker).
measure the insulation resistance again.
pressor. The resistance will rise above 1 M
up for four hours.
(The time necessary to warm up the compressor varies according to atmospheric
conditions and refrigerant accumulation.)
compressor must be warmed up at least 12 hours to prevent breakdown.
Caution:
is correct.
in severe damage to internal parts. Keep the power switch turned on during the
operational season.
when the outdoor unit is faulty.
SW3-1
Cooling operation
SW3-2 OFF
SW3-1
Heating operation
SW3-2
the inside of the outdoor unit. The noise is coming from the check valve due to the
small difference in pressure in the pipes. The unit is not faulty.
* If too much refrigerant has been added to the air conditioner system, the pressure
2 . If this occurs, use a refrigerant collecting device
to collect all of the refrigerant in the system, and then recharge the system with
the correct amount of refrigerant after the indoor and outdoor units have been
relocated.
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after the compressor is warmed
2 )
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