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Honey well zone valves and oxygen

joseph annon
joseph annon Member Posts: 53
I have a system I am working on that has what I think  solaroll for radiant floor staple up.

The problem is that when one zone calls for heat all zones get heat.

The pump is probably over sized at a up26-96f. Not bronze either.

House about 3,000 square feet and 6 zones so some are fairly small.

Possibilities I see are pump is forcing valves open. ( however customer says problem is recent and not related time wise to pump) Or that the ball in the Honeywell valves has eroded and doesn't ever completely close.

So one question is are the balls in the Honeywell zone valves sensitive to oxygenated boiler water.

If there are other possibilities let me know what I can look for.

Back ground on system previous services performed were zone valve power head replacement to fix end switch not working. Then all zones wired together to provide heat to house then a zone controller added so that valve operation could be monitored. Then I was called for all zones heating on a call from one thermostat.

Thank You Joe Annon


  • Zman
    Zman Member Posts: 7,569
    Zone valve


    The oxygen itself should not effect the valve.

    The problem comes when all the byproducts of the oxygen corroding the other system parts start floating around the system.

    It is very possible that the "cocktail" of chemicals and whatnot  in the system damaged the valve. If you can isolate the valve, it doesn't take  much to open one up.

    It sounds like you have a sizable circulator deadheading into the zone valves? is there a differential  bipass?

    It seems like customers always indicate that it is a new problem in order to motivate you to take care of it.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • joseph annon
    joseph annon Member Posts: 53
    Differential bypass

    There is not one installed. That will be part if not all of the solution. Am trying to eliminate other possibilities before starting to tear into the system.
  • Snowmelt
    Snowmelt Member Posts: 1,414

    One of john from taco webinar said a bypass is a bandaid for something not done correctly.

    It's summer now so it's hard to really replace something to see if it works.

    If it's zone valves I would be thinking about replacing it with a variable speed or a bumble bee.

    I say do the math first.
  • joseph annon
    joseph annon Member Posts: 53
    VSR pumps and non barrier tubing

    A VSR pump  is a possibility in the correct range.

  • Plumdog_2
    Plumdog_2 Member Posts: 873
    I have to answer Yes to your question

    I came across an 'open' system that had been converted to 'closed', all the tubing being PB. Had about 8 of those zone valves, two of them had the shaft rust thru, allowing the ball to break free and become stuck fast into the outlet side of the valve. All the others had a rust gumball blocking the stem from turning. The only other steel or iron on the system was the expansion tank, as far as I know.