Test Run; Before Test Run; Using Remote Controller; Using Sw3 In Outdoor Unit - Mitsubishi Electric CITY MULTI PUMY-SP125VKM Installationshandbuch

7. Test run

7.1. 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 M-ohm tester to check that the resistance between the power
supply terminals and ground is at least 1 MΩ.
► 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 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 resistance
dropped due the accumulation of refrigerant in the compressor.
7.2. Test run

7.2.1. Using remote controller

Refer to the indoor unit installation manual.
• Be sure to perform the test run for each indoor unit. Make sure each indoor
unit operates properly following the installation manual attached to the unit.
• If you perform the test run for all indoor units at once, you cannot detect any
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.
• The compressor can emit noise just after turn on the power supply or in case
of low outside air temperature.
About the restart protective mechanism
Once the compressor stops, the restart preventive device operates so the compressor
will not operate for 3 minutes to protect the air conditioner.
7.3. Refrigerant collecting (Pump down)
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
after the power (circuit breaker) is turned ON.
5 Confirm that SW3-2 is set to OFF, and then set SW3-1 to ON to perform the test
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
service switch SW2-4 (pump down switch) from OFF to ON.
* Do not continue to operate for a long time with the switch SW2-4 set to ON. Make
sure to switch it to OFF after pump down is completed.
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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 12 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. LED 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.

7.2.2. Using SW3 in outdoor unit

Note:
In case of the test run from outdoor unit, all indoor units operate. Therefore,
you can not detect any erroneous connection of refrigerant pipes and the con-
necting wires. If it aims at detection of any erroneous connection, be sure to
carry out the test run from remote controller with reference to "7.2.1. Using
remote controller."
■ Test run (from the outdoor unit)
1 Set SW3-2 to select the operation mode.
ON Heating operation
SW3-2
OFF Cooling operation
2 After setting SW3-2, set SW3-1 from OFF to ON. The test run starts.
* Before setting SW3-1, make sure that the circuit breaker is turned on.
* If the setting for SW3-2 is changed during the test run, the operation mode will
change.
* Set SW3-1 to OFF to finish the test run.
• 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.
6 Fully close the gas stop valve when the pressure reading on the gauge drops
0.05 - 0.00 MPa (approximately 0.5 - 0.0 kgf/cm
7 Stop the air conditioner operation (SW3-1: OFF). Set the outdoor service switch
SW2-4 from ON to OFF.
8 Turn off the power supply (circuit breaker).
* If too much refrigerant has been added to the air conditioner system, the pres-
sure may not drop to 0.05 MPa (0.5 kgf/cm
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.
Warning:
When pumping down the refrigerant, stop the compressor before disconnect-
ing the refrigerant pipes. The compressor may burst and cause injury if any
foreign substance, such as air, enters the system.
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2 ). If this occurs, use a refrigerant