Troubleshooting Refrigerant Circuit Problems (Continued)
TXV Stuck Open:
•Head pressure will be slightly to moderately low;
•Suction pressure will be slightly high to very high;
•Amperage (not a reliable indicator of this condition);
•Liquid subcooling will be lower than normal;
•Superheat will be minimal or nonexistent;
•Suction line, and possibly a large portion of compressor, will be very cold and possibly “sweating”. Explanation: Refrigerant is flowing through the system too quickly; enough heat cannot be added in the evaporator to boil off all the liquid refrigerant. The main effect is to flood the suction line and compressor with liquid refrigerant. The primary indicator of this condition is little or no suction line superheat. Also, as the TXV is not holding back the required amount of refrigerant, there may be flash gas
Insufficient Condenser Water Flow:
•Head pressure will be moderately high to very high;
•Suction pressure my be normal to slightly high;
•Amperage will be higher than normal;
•Liquid subcooling will be absent; the liquid line will be very warm or even hot to touch. When combined with high condenser water ∆T (see next bullet item), this condition is a prime indicator of insufficient condenser water flow;
•Condenser
•Superheat will be
Explanation: Heat is not being removed in the condenser in quantities sufficient to produce appreciable amounts of liquid refrigerant. With no liquid seal occurring in the condenser, the liquid
Refrigerant Circuit Performance Charts
Use of Charts- Information for the Technician:
The charts are intended for use by trained and qualified
38