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PROBLEM P OSSIBLE CAUSE REMARK
Air filter Clean or replace if restricted.
Vent door Close if open.
Unit undersized
Determine if the unit is properly sized for
the area to be cooled or heated.
Condenser and Evaporator Clean if restricted.
Fan motor
Check the fan capacitor and replace if not
within +/-10% of manufacturer’s rating.
Room structure
Take proper measures to make sure doors
and windows are sealed well.
Air flow
Clean or remove if any barrier is found to
block the inlet/outlet wind flow of the unit
(drapes, shrubs, etc.).
Sunlight
Add a awning if the unit is exposed to direct
sunlight or move the unit to another window
that’s not exposed to direct sunlight.
Refrigerant loss
Check the tubes for leakage. Reclaim the
refrigerant, correct the leakage points and
recharge.
Capillary tube
Regulate the flow of capillary tube and
ensure the evaporating temperature is
appropriate, if the evaporator is frosted.
Replace if blocked. Repair joint if leaking.
Compressor
The inlet and outlet valve of the
compressor may be damaged, making the
low pressure connected with the high
pressure. The refrigerating system can not
produce high pressure and low pressure.
Replace the compressor after checking for
the reason of failure.
Heat sources
Reduce if too many (dryers, electric
heaters, small appliances, etc.)
Insufficient cooling
or heating.
Drainage
If drainage is blocked it will increase the
efficiency in cooling mode, but will cause
the condenser to frost in heating mode.
Remove any obstacles.
Refrigerant
If the amount of the refrigerant is too large,
making the compressor load too large.
Reclaim and recharge the refrigerant after
checking for the reason of failure.
Stop instantly after
startup.
Compressor
The compressor is seized. Replace after
checking for the reason of failure.
Service Manual
Room Air Conditioner with R-410A
Heat Controller, Inc.
28