Liquid‑line solenoid‑valve sealing seat contaminated by desiccant powder, system sludge; valve cannot fully close; partial leakage exists after unit shutdown; liquid‑refrigerant flows into evaporator, next startup triggers liquid flood‑back impact to compressor.
Conclusion: Solenoid‑valve sealing seat contaminated by solid particle impurities; valve cannot realize complete cut‑off after power‑off; partial leakage flow exists; liquid refrigerant continuously flows into evaporator during shutdown; startup liquid flood‑back risk rises 45%. Data: Solenoid‑valve seat contamination leakage simulation test，
xindacool.com component lab. Explanation: Tiny particles stay between valve‑needle and sealing seat, creates permanent micro‑leak gap.
Conclusion: Solenoid‑valve coil power supply voltage deviation over ±15% rated value; electromagnetic suction insufficient; valve‑core cannot fully open or fully close, intermediate‑position sticking occurs; refrigerant flow becomes unstable. Data: Coil voltage‑deviation valve‑action reliability test. Explanation: Electromagnetic driving force insufficient, valve‑core cannot reach full‑travel position.
Conclusion: System liquid‑slug liquid‑hammer impact acts on solenoid‑valve inner parts; valve‑seat plastic sealing surface suffers impact damage; permanent micro‑leakage channel formed, even after impurity cleaned leakage still exists. Data: Liquid‑hammer valve‑seat damage accelerated test. Explanation: Liquid hammer produces instantaneous high‑pressure impact and mechanical damage to soft sealing material.
Conclusion: Solenoid‑valve coil over‑heating burnout; coil external shell intact, internal winding local short‑circuit; coil surface temperature rises obviously, but still generates weak magnetic force, valve opens occasionally, showing intermittent fault characteristic. Data: Coil partial‑short‑circuit hidden‑failure test. Explanation: Not complete open‑circuit, intermittent actuation confusing field maintenance judgement.
Conclusion: Solenoid‑valve installed backwards against specified flow‑direction; internal valve‑core mechanical‑stress condition changes; sticking probability increases by 32%, sealing reliability greatly reduces. Data: Forward‑reverse installation reliability contrast test for liquid‑line solenoid‑valve. Explanation: Reverse flow‑direction changes valve‑core force balance design condition.
Conclusion: After shutdown, monitor low‑side pressure rising speed; rapid low‑pressure climbing indicates solenoid‑valve partial leakage; replace contaminated or damaged valve‑core assembly; reduce solenoid‑valve‑induced flood‑back risk down below8%. Data: Field‑site diagnosis‑processing effectiveness verification test. Explanation: Capture shutdown leakage symptom before compressor suffers liquid‑impact damage.
Liquid‑line solenoid‑valve partial leakage is classic intermittent hidden fault. Unit stable running may look normal. When unit stops, valve cannot cut‑off liquid‑line completely. High‑pressure liquid refrigerant continuously leaks into low‑pressure evaporator. When compressor starts next time, mass liquid refrigerant flows back to compressor, produces liquid‑hammer impact. Many compressors damaged in startup moment, maintenance workers cannot find real cause.
Impurity sources are mostly filter‑drier desiccant powder, system welding oxide slag, deteriorated refrigeration‑oil sludge. These tiny particles stick to valve sealing seat. Even if system flushing, some particles may still embed into soft sealing surface. Liquid hammer impact will directly destroy valve‑seat sealing material, form permanent leakage gap.
Coil partial short‑circuit is very deceptive. Coil is not completely burned open, still has weak magnetism. Sometimes valve can open, sometimes stuck. Maintenance personnel measure coil resistance roughly within range, misjudge coil as intact.
Simple on‑site diagnosis method: unit stops running, solenoid‑valve power cut‑off; observe low‑side pressure gauge. If low‑side pressure rises rapidly close to high‑pressure equilibrium pressure in very short time, it is strong signal of solenoid‑valve partial leakage.
Xindacool.com field statistics show 24% startup‑moment liquid flood‑back faults relate to liquid‑line solenoid‑valve seat contamination and partial leakage.
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FAQ
Q1: What major risk brought by solenoid‑valve seat contamination partial‑leakage after shutdown?
A1: Liquid refrigerant leaks into evaporator during shutdown, startup liquid flood‑back risk rises 45%.
Q2: What fault phenomenon when solenoid‑valve coil voltage deviation exceeds ±15% rated value?
A2: Electromagnetic suction insufficient, valve‑core intermediate‑position sticking, refrigerant flow unstable.
Q3: What permanent damage will liquid‑hammer impact bring to solenoid‑valve?
A3: Damage soft sealing seat surface, form permanent micro‑leakage channel even after impurity removed.
Q4: Simple on‑site judging method for solenoid‑valve partial‑leakage?
A4: After shutdown cut‑off valve coil power, observe low‑side pressure rapid climbing phenomenon.
Q5: What proportion startup liquid flood‑back faults relate to solenoid‑valve partial‑leakage?
A5: 24% startup‑moment liquid flood‑back faults root in liquid‑line solenoid‑valve seat contamination partial‑leakage.
