Test Run (Only For Air-Conditioners) - Mitsubishi Electric PUHZ-SHW HA Series Installation Manual

8. Test run (Only for Air-Conditioners)

8.1. Before test run
► After completing installation and the wiring and piping of the indoor and
outdoor units, check for refrigerant leakage, looseness in the power supply
or control wiring, wrong polarity, and no disconnection of one phase in the
supply.
► Use a 500-volt megohmmeter to check that the resistance between the pow-
er supply terminals and ground is at least 1 MΩ.
► Do not carry out this test on the control wiring (low voltage circuit) termi-
nals.
Warning:
Do not use the outdoor unit if the insulation resistance is less than 1 MΩ.
Insulation resistance
After installation or after the power source to the unit has been cut for an extended
period, the insulation resistance will drop below 1 MΩ due to refrigerant accumulat-
ing 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 MΩ, 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,
measure the insulation resistance again.
8.2. Test run
8.2.1. Using SW4 in outdoor unit
SW4-1 ON
Cooling operation
SW4-2 OFF
SW4-1 ON
Heating operation
SW4-2 ON
* After performing the test run, set SW4-1 to OFF.
• After power is supplied, a small clicking noise may be heard from the inside of the
outdoor unit. The electronic expansion valve is opening and closing. The unit is
not faulty.
• The insulation resistance drops due to accumulation of refrigerant in the com-
pressor. The resistance will rise above 1 MΩ after the compressor is warmed up
for 4 hours.
(The time necessary to warm up the compressor varies according to atmospheric
conditions and refrigerant accumulation.)
• To operate the compressor with refrigerant accumulated in the compressor, the
compressor must be warmed up at least 12 hours to prevent breakdown.
4. If the insulation resistance rises above 1 MΩ, the compressor is not faulty.
Caution:
• The compressor will not operate unless the power supply phase connection
is correct.
• Turn on the power at least 12 hours before starting operation.
- Starting operation immediately after turning on the main power switch can result
in severe damage to internal parts. Keep the power switch turned on during the
operational season.
► The followings must be checked as well.
• The outdoor unit is not faulty. LED1 and LED2 on the control board of the outdoor
unit fl ash when the outdoor unit is faulty.
• Both the gas and liquid stop valves are completely open.
• A protective sheet covers the surface of the Dip switch panel on the control
board of the outdoor unit. Remove the protective sheet to operate the Dip
switches easily.
• A few seconds after the compressor starts, a clanging noise may be heard from
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.
The test run operation mode cannot be changed by Dip switch SW4-2 during
the test run. (To change the test run operation mode during the test run, stop
the test run by Dip switch SW4-1. After changing the test run operation mode,
resume the test run by switch SW4-1.)
8.2.2. Using remote controller
Refer to the indoor unit installation manual.
Note : Occasionally, vapor that is made by the defrost operation may seem as
if smoke come up from the outdoor unit.
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