Test Run; Before Test Run - Mitsubishi Electric Mr.Slim PUHZ-P HA Série Manuel D'installation

6. Electrical work
Warning:
In case of A-control wiring, there is high voltage potential on the S3 terminal caused by electrical circuit design that has no electrical insulation between power
line and communication signal line. Therefore, please turn off the main power supply when servicing. And do not touch the S1, S2, S3 terminals when the power
is energized. If isolator should be used between indoor unit and outdoor unit, please use 3-poles type.

7. Test run

7.1. Before test run

s 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.
s Use a 500-volt megohmmeter to check that the resistance between the power
supply terminals and ground is at least 1.0MΩ Ω Ω Ω Ω .
s Do not carry out this test on the control wiring (low voltage circuit) terminals.
Warning:
Do not use the air conditioner if the insulation resistance is less than 1.0MΩ Ω Ω Ω Ω .
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.
• 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 four hours.
(The time necessary to warm up the compressor varies according to atmos-
pheric conditions and refrigerant accumulation.)
7.2. Test run
7.2.1. 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.
8
230V
Single phase
Isolator
S1
A-Control
S2
Outdoor Unit
S3
3 poles isolator
S1
A-Control
S2
Indoor Unit
S3
• 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 op-
erational season.
s The followings must be checked as well.
• The outdoor unit is not faulty. LED1 and LED2 on the control board of the outdoor
unit flash 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.)
7.2.2. Using remote controller
Refer to the indoor unit installation manual.