Wednesday, July 06, 2011

Schematic Diagram Download

Troubleshooting a Solenoid Valve: Problem 2



Valve closes, but flow continues (seat leaking)

Cause:
Foreign materials lodged under seat.

Corrective Action:
Clean internal parts and remove foreign material

Cause:
Valve seat damaged.

Corrective Action:
Replace valve or affected parts.

Cause:
Synthetic seat materials chipped.

Corrective action:
Replace valve or affected parts.

Cause:
Valve improperly applied or assembled.

Corrective action:
Replace valve with proper valve or reassemble.





Troubleshooting a Solenoid Valve: Problem 1

Normally closed valve will not close
Or normally open valve will not open

Causes:

Diaphragm or plunger restricted due to corroded parts, foreign materials lodged in valve, dented or bent closing tube, or warped body due to improper brazing or crushing in vise.

Corrective Action:

Clean affected parts and replace parts as required. Correct the cause of corrosion or source of foreign materials in the system. Install a filter drier upstream of solenoid valve.

Causes:

Manual opening stem holding valve open.

Corrective Action:

With coil de-energized, turn manual stem in counter clockwise direction until valve closes.

Causes:

Closing spring missing or inoperative.

Corrective Action:

Reassemble with spring in proper position.

Causes:

Electrical feedback keeping coil energized or switch contacts not breaking circuit to coil.

Corrective Action:

Attach voltmeter at coil leads and check for feedback or closed circuit. Correct faulty contacts or wiring.

Causes:

Reverse pressures (outlet pressure greater than inlet pressure) or valve installed backwards.

Corrective Action:

Install check valve at valve outlet, or install with flow arrow to proper direction.


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