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TROUBLESHOOTING
Restricted Refrigerant System
NOTE: Ensure fan is on high speed during testing.
Troubleshooting a restricted refrigerant system can be difficult. The following procedures are the more common problems and
solutions to these problems. There are two types of refrigerant restrictions: Partial restrictions and complete restrictions.
A partial restriction allows some of the refrigerant to circulate through the system.
With a complete restriction there is no circulation of refrigerant in the system.
Restricted refrigerant systems display the same symptoms as a "low-charge condition."
A quick check for either condition begins at the evaporator. With a partial restriction, there may be gurgling sounds at the metering
device entrance to the evaporator. The evaporator in a partial restriction could be partially frosted or have an ice ball close to the
entrance of the metering device. Frost may continue on the suction line back to the compressor.
Often a partial restriction of any type can be found by feel, as there is a temperature difference from one side of the restriction to the
other. There will ususally be a diiference felt at the capillary tube. This does not indicate a restricted condition.
With a complete restriction, there will be no sound at the metering device entrance. An amperage check of the compressor with a
partial restriction may show normal current when compared to the unit specification. With a complete restriction the current drawn
may be considerably less than normal, as the compressor is running in a deep vacuum (no load.) Much of the area of the condenser
will be relatively cool since most or all of the liquid refrigerant will be stored there.
Make all checks posible before tapping into the system and installing gauges.
When the unit is shut off, or the compressor disengages, the gauges may equalize very slowly.
The following conditions are based primarily on a system in the cooling mode.
Figure 603 (Restricted System)
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