Service and Parts Manual (2019, 2020, 2021, 2022)

28 PB
Metering Device - Capillary Tube Systems
All units are equipped with capillary tube metering devices. Checking for restricted capillary tubes.
1. Connect pressure gauges to unit.
2. Start the unit in the cooling mode. If after a few minutes of operation the pressures are normal, the check valve and the
cooling capillary are not restricted.
3. Switch the unit to the heating mode and observe the gauge readings after a few minutes running time. If the system
pressure is lower than normal, the heating capillary is restricted.
4. If the operating pressures are lower than normal in both the heating and cooling mode, the cooling capillary is restricted.
COOLING MODE
In the cooling mode of operation, liquid refrigerant from condenser (liquid line) enters the cooling check valve forcing the
heating check valve shut. The liquid refrigerant is directed into the liquid dryer after which the refrigerant is metered through
cooling capillary tubes to evaporator. (Note: liquid refrigerant will also be directed through the heating capillary tubes in a
continuous loop during the cooling mode).
COMPONENT TESTING
Hermetic Components Check
BURN HAZARD
Proper safety procedures must be followed,
and proper protective clothing must be worn
when working with a torch.
Failure to follow these procedures could
result in moderate or serious injury.
WARNING
WARNING
CUT/SEVER HAZARD
Be careful with the sharp edges and corners.
Wear protective clothing and gloves, etc.
Failure to do so could result in serious injury.