Zone valves sticking

John_4

Working on a house with radiant heat throughout. Non-barrier pex tubing, and zone valves that bind up every three years or so. The lubrication on the stem gets washed away and the o-rings on the zone valves deteriorate after two or three years. Same type of valves installed in other job sites don't have a problem. The first time it happened three years ago, the lubricant was gone from the o-rings and the o-rings themselves were deteriorating. The manufacturer took water sample and said everything was OK. Put new valves in and the stems are starting to bind up again. The only thing I can think of is that something is in the water causing this problem. Any suggestions on what to look for in a water sample? Could non-barrier pex be causing a problem? The only other thing that could cause a problem on this system that I can see is that there is a Grundfos UP25-64SF, six zone valves and no pressure differential bypass, but that should not have anything to do with the stems sticking. Any help would be appreciated.

hr

That's not natural!

I would suspect a water quality issue also. Find some one that can test ph, hardness, tds, iron, etc. Someone that specializes in boiler or cooling tower treatment would have the knowledge and equipment to test for the right, or wrong, quality.

An o-ring should function without lubrication, as most have lubrication ability built into the material of the ring. Sounds like you have a bug or something eating your rings.

Maybe LEGIONELLA. Just kidding!

Hydronic system cleaner and conditioner may be helpful to get you back on track. Sometimes I have to import water for hydronic fills on homes with bad well water. Most cities have warer condition companies that will sell you filtered water in 5 or 50 gallon quantities. I buy DI water for 7 cents a gallon locally. It needs to have the conditioners added to bring the ph and protection levels to an acceptable range, however.

Let us know what you find.

hot rod

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Fred Harwood

Valves sticking

I have had such terrible luck with rotating core zone valves sticking that I change them out for ball-type as soon as they begin sticking. I got real tired of cleaning them, re-o-ringing, and futzing with them, just the have them stick again next year.

mike glass

Rotating O-rings

I think hotrod is on the money! In our area (Columbia, MO),
W/R rotating zone valves are the norm with very seldom an O-ring failure.

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