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Andy Dixon



Tuesday, March 9th 2010, 3:06pm

Zone valve not closing

I have a six zone system. I have identified a problem to one of the zone valves not closing which keeps that zone running permanently or until I close the water supply valve so the pump shuts down when reaching correct pressure.

I have proven that the control voltage to the solenoid stops on time but the valve does not close. The valve top (spring, diaphragm and valve body top) has been changed but I still have the same problem.

Is this problem associated with the valve spring not being strong enough to close the valve against water pressure. Do I have to change the whole valve or can I repair with a stronger spring?



Posts: 2,319

Location: USA


Tuesday, March 9th 2010, 5:06pm

There might be some debris inside the valve keeping the diaphram from closing.

Make sure the solenoid plunger isn't stuck open.

I'd double check the installitaion of the new parts.

Don't worry about finding a stronger spring. The one you have is the correct spring.

Does the valve attempt to close at all?

Which model valve do you have.

Why do I get the strange feeling this valve is on a dripline...

Andy Dixon



Wednesday, March 10th 2010, 9:32pm

Thanks for the help so far.

I will re-check for debris inside the valve keeping the diaphragm from closing but the valve seems to stay fully open and all four sprinkler heads operate at full bore, not just a trickle as I would expect if debris was in there.

I'll also ensure the solenoid plunger isn't stuck open but this is part of the new valve top so I would hope that the new one didn't have the same problem as the one I changed out.

Spring should be OK - thanks.

The valve doesn't seem to close at all. The control voltage goes but the valve stays (wide) open to give full bore flow at the heads. Valves are Nelson type.

Not sure what a dripline is but I don't think I have one. Pump - valves – pipe work - sprinkler heads, simple as that.

This zone stayed on for about an hour (today) after it should have cut off. Can't see what would cause it to do that as it suggests that the "problem" suddenly goes away??? Would a low pressure surge allow the valve to close?

Any more help gratefully received.


Senior Member

Posts: 15

Location: Montana


Saturday, March 27th 2010, 9:01pm

Nelson valves are very suspect to dirt under the solenoid. Try taking the solenoid off and rinsing out any grains of dirt/sand that are inside, and hand tightening the solenoid back on.

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