Zone Valve - Complete Shutoff

Old 06-04-05, 02:41 PM
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Zone Valve - Complete Shutoff

I want to use a brass zone valve to control my drip watering system. (I've been using standard plastic sprinkler system valves outside, but I don't want to keep taking the system apart in the winter.) I figure that a zone valve won't leak and make a mess in the house.

So I bought a Taco Zone valve and installed it along with a pressure regulator. No water leaks in the house. But I find that the valve doesn't shut off completely (even if I remove the power head). Maybe it's a problem with the valve, but I took everything apart and it looks pretty clean.

I see that some valves have a "maximum shutoff pressure", or a "maximum differential pressure" and now I'm thinking that maybe these valves aren't designed to operate with full house pressure on one side and no pressure at all on the other side. I can't see why this would be from looking at the valve taken apart, but you never know.

Any ideas from those smarter than I?

Old 06-04-05, 09:00 PM
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Zone valve

You are correct in your thoughts about pressure. Most zone valves are not intended to be used under house pressure. If you need an electricly operated valve, I might suggest a solenoid valve similar to those used in a washing machine. If this is drip irrigation, you should not need much pressure. You could install a reducing valve ahead of the zone valve. These come preset at 12 psig but can be adjusted.
Old 06-04-05, 11:38 PM
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High Pressure for Zone Valve


Thanks for the post!

You're right that the valves work better with lower pressure. (But they say that are rated at 125 PSI.) The drip system I have is rated for use between 15 and 25 PSI, I've got a lot of drippers and wanted a little higher pressure than the minimum.

When I installed it initially, it was on the low pressure side of the reducing valve and leaked enough to hear the water flow. Based on the way the valve was designed, I installed it on the high pressure side because I thought that the extra water pressure might push harder against the valve plate, but that was worse.

So I took the pipes apart yet again and put it back together again with the valve on the low pressure side, and now it drips a little bit but is silent. I can live with a little dripping outside, though that will be a problem in the winter.

The White-Rodgers and Honeywell valves are rotating type (like a ball valve, it appears), the Taco I have uses a spring to hold a disk (with rubber O-ring) against an opening. So I could bet that the others might do better with a little more water pressure. Plus the Taco is high power (0.90A) which is a hassle on the controller side. Maybe a bad choice of valves for this application.

I suppose in a typical hot water heating system a little leaking through the valve wouldn't matter too much.

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