Mitsubishi Electric TRANE NTXAMT12A112AA Manuel D'installation page 48

14. Test run
14.1. 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 power supply terminals and ground is at least 1.0 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 1.0 MΩ.
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 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 MΩ, the compressor is faulty or the resistance 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 compressor. The resistance will rise above
1 MΩ after the compressor is warmed up for two to three 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.
14.2. Test run
Refer to the installation manual that comes with each remote controller for details.
Specifications are subject to change without notice.
NTXAMT12, 18, 24, 30, 36A112AA
48 © 2018 Mitsubishi Electric Trane HVAC US LLC. All rights reserved.