Crystallizer Valve — Wiring & Troubleshooting
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CH.03 CRYSTALLIZER VALVE — WIRING & TROUBLESHOOTING REF-03-A // WIRING — CRYSTALLIZER FILL VALVE (TYPICAL) PLC PANEL DO Card — Ch.1 120VAC OUTPUT 120V L1 COM DI Card — Ch.1,2 ZSO ZSC COM 120VAC L1 → SOL ZSO ZSC SOLENOID 120VAC / 1500–3000Ω T1 (L1) T2 LED AIR ACTUATOR Spring-return Pneumatic VALVE BODY DISC / PLUG WESTLOCK Cam-operated 120V L1 T3→ZSO COM T4→ZSC cam ZSO → PLC DI ZSC → PLC DI // WIRE COLOR KEY +120VAC L1 (hot) Neutral (N) return ZSO — Open confirm ZSC — Closed confirm Pneumatic air supply // FAULT DIAGNOSIS — WIRING & LIMIT SWITCHES FAULT: Commanded OPEN — PLC still shows CLOSED ① Check solenoid LED — lit? If NO → 120VAC not reaching solenoid ② Measure VAC at T1-T2 of solenoid — should read 120VAC when ON ③ If solenoid lit but valve not moving → check air supply PSI ④ If valve moved but ZSO dark → Westlock cam slipped or switch dead FAULT: Valve is OPEN but PLC shows CLOSED ① Physically verify valve is open (stem position, check flow) ② ZSO not reaching PLC — measure voltage at DI card input terminal ③ If 0V → broken wire, or cam not reaching ZSO switch actuator FAULT: Both ZSO and ZSC showing ON at same time ① Impossible in normal operation — one must always be OFF ② Likely: 120VAC backfeed through failed relay contact or wiring fault ③ Disconnect wires one at a time to isolate the short path FAULT: Solenoid coil overheating / burned out ① Measure coil resistance — normal: 1500–3000Ω / shorted: <10Ω / open: ∞ ② Coil rating: 120VAC for all crystallizer solenoids — never swap with 24VDC coil ③ Check duty cycle — continuous vs intermittent rating // FAST TEST PROCEDURE STEP 1 Force PLC DO ON → confirm solenoid LED lights STEP 2 Measure VDC T1-T2 → should read 120VAC STEP 3 Push manual override → does valve move? (mech vs elec isolation) STEP 4 Check PSI at actuator port → rises when solenoid energizes STEP 5 Manually trigger Westlock cam → ZSO/ZSC change in PLC? // EXPECTED SIGNAL STATES BY VALVE CONDITION VALVE STATE PLC DO OUTPUT SOLENOID LED ZSO (OPEN) ZSC (CLOSED) AIR PSI FULLY CLOSED OFF (0V) OFF OFF (0V) ON (120VAC) 0 PSI FULLY OPEN ON (120VAC) ON ON (120VAC) OFF (0V) 20–30 PSI MID-TRAVEL ON (120VAC) ON OFF OFF rising // INSTRUMENTATION FIELD MANUAL — CH.03 CRYSTALLIZER VALVE 03_Crystallizer_Valve/Crystallizer_Wiring_Troubleshooting.svg
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