R-Pro › Field cases › Refrigeration systems
Low Pressure Drop from Expansion Valve Blockage / Closure
Likely causes
Expansion valve frozen by moisture
Check: Confirm blockage by measuring temperature/pressure across valve
What to do: Confirm blockage by measuring temperature/pressure across valve → TXV: check sensing bulb gas charge → Replace filter drier → Recover refrigerant and replace expansion valve → Evacuate and recharge
Debris/sludge blockage
Check: TXV: check sensing bulb gas charge
What to do: TXV: check sensing bulb gas charge → Replace filter drier → Recover refrigerant and replace expansion valve → Evacuate and recharge
TXV closed from sensing bulb gas loss
Check: Replace filter drier
What to do: Replace filter drier → Recover refrigerant and replace expansion valve → Evacuate and recharge
Expansion valve blocked or closed, cutting off refrigerant supply to the evaporator. Inspect or replace.
All 565 cases work offline in R-Pro, with error codes for 62 brands and P-T data for 108 refrigerants.
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