About Insulation Resistance - Hitachi RAS-(3-6)HVNC1(E) Service Manual

7 Test run
• Check to ensure the operating temperature:
- Cooling operation:
Š Indoor DB 21.5ºC and above,
Š Indoor WB 16ºC and above,
Š Outdoor DB 0ºC and above
- Heating operation:
Š Indoor DB 27ºC and below.
(*) About insulation resistance
• The insulation may lower during a test run or after being left with the main power OFF for a long time, due to refrigerant
accumulation in the compressor. Check the following when the insulation resistance lowers to 1 MΩ or below, or in case
that the ground-fault circuit interrupter activates.
1 Remove compressor cables and measure the insulation resistance of the compressor alone. If the resistance is
over 1 MΩ, other insulation failure of electric live part may exist.
2 If the resistance is under 1 MΩ, remove compressor cables from the inverter PCB and turn the power ON and
energize the oil heater. Measure the resistance after more than three hours of electric current application. If the
insulation resistance recovers, the compressor does not have problems. In case that the resistance does not reco-
ver, compressor failure may exist. (More time may be required to apply the current depending on the conditions of
air, pipe length or the refrigerant).
N O T E
To reconnect the removed compressor cables, re-caulk the terminal using a tool like longnose pliers in order that
the Faston terminal does not remain loose.
• In case of Earth Leakage Breaker (ELB) activation, please confirm the rated capacity of ELB as well. Earth leakage
breaker (ELB) shall be inverter compatible, and select a high-sensitive and high-speed model for sensed current rating
under 30 mA (activation time within 0.1 sec).
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SMGB0087 rev.0 - 12/2013
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