Receiver Outlet Liquid-Line Solenoid Fault (Pump-Down Failure / Supply Cutoff)
A field reference for liquid receiver faults — what causes it, how to confirm it on the unit, how to repair it, and what fails next if you leave it. Written for working HVAC & refrigeration technicians.
How to confirm it on site
- Coil resistance: normal 24~50Ω depending on maker; ∞ = open, 0Ω = short
- 24V applied → coil hums / vibrates = OK; no response = coil fault
- Magnet test: remove coil, magnet near slide → if slide moves, body OK and coil is the fault
- Touch external surface: input vs output big temperature difference → partial blockage / stuck closed
- On startup: no clicking sound = coil or slide not actuating
Root causes
- Coil insulation aging / thermal degradation
- Overvoltage / surge (lightning)
- Seat stuck closed by debris / sludge
- Wire break / terminal corrosion
- Wrong voltage applied
If you leave it unrepaired
- Coil open → valve closes (fail-safe) → liquid supply cut → compressor LP trip
- Stuck closed during pump-down command → continuous flow when needed → liquid migration on stop
- Partial failure → restricted flow → liquid line pressure drop → capacity loss + suction superheat rise
- Stuck open at setpoint reached → continuous run → over-capacity + icing risk
- If left: compressor damage or system reliability decline
How to fix it
- Replace coil only if coil is the fault (no need to break valve body)
- Replace solenoid body if internal fault
- After replacement: clean system + new filter-drier + vacuum + acid test
- Verify voltage rating + terminal torque + surge protection
- Prevention: annual coil resistance / actuation test
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What causes receiver outlet liquid-line solenoid fault (pump-down failure / supply cutoff)?
Coil insulation aging / thermal degradation Overvoltage / surge (lightning) Seat stuck closed by debris / sludge Wire break / terminal corrosion Wrong voltage applied
How do I diagnose receiver outlet liquid-line solenoid fault (pump-down failure / supply cutoff) on site?
Coil resistance: normal 24~50Ω depending on maker; ∞ = open, 0Ω = short 24V applied → coil hums / vibrates = OK; no response = coil fault Magnet test: remove coil, magnet near slide → if slide moves, body OK and coil is the fault Touch external surface: input vs output big temperature difference → partial blockage / stuck closed On startup: no clicking sound = coil or slide not actuating
How do I fix receiver outlet liquid-line solenoid fault (pump-down failure / supply cutoff)?
Replace coil only if coil is the fault (no need to break valve body) Replace solenoid body if internal fault After replacement: clean system + new filter-drier + vacuum + acid test Verify voltage rating + terminal torque + surge protection Prevention: annual coil resistance / actuation test
What happens if receiver outlet liquid-line solenoid fault (pump-down failure / supply cutoff) is left unrepaired?
Coil open → valve closes (fail-safe) → liquid supply cut → compressor LP trip Stuck closed during pump-down command → continuous flow when needed → liquid migration on stop Partial failure → restricted flow → liquid line pressure drop → capacity loss + suction superheat rise Stuck open at setpoint reached → continuous run → over-capacity + icing risk If left: compressor damage or system reliability decline