Friedrich SS15N30* ユーザーズマニュアル

40

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.” 
When the unit is shut off, the gauges may equalize very  

slowly. 
Gauges  connected  to  a  completely  restricted  system 

will run in a deep vacuum. When the unit is shut off, the 
gauges will not equalize at all.
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. 
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 specifi cation. 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. 
The following conditions are based primarily on a system 

in the cooling mode.