O-ring on Honeywell zone valve keeps blowing out

BillW@honeywell

It sounds like the pressure is ok, these valves are capable of closing off against 20 psi. Is a petroleum based antifreeze solution being used in this system? The material that the O ring is made of is EPDM, which works well in the hydronic world. Any problems with the ball swelling up or softening? Please get me the date codes of these valves, if possible.

molly

O-ring

Hello guys. This one has me stumped. I've got a new customer with a System 2000 dressed out in 11/4" with 4 3/4" Honeywell zone valves and a 40gal hot water heater with the transfer plate. One of the zone valves has blown the o-ring out twice in 3 months. I show up and it's squeezed out of the valve body. The first time one of the four bolts that holds the valve body together was broken off. I thought maybe the former tech had replaced the o-ring and overtightened one bolt and broken it off. I replaced the complete valve and to my surprise it squished out again about 3 months later. It's happened only on this one zone. The pressure is about 15psi. The expansion tank is good. The t/p relief valve works. Any suggestions or comments would be much appreciated.

B. Tice

Zone valve

I would make sure the by pass is OK. System 2000 is a little tough on zone valves if by pass is not open.

Bob Bona_4

pump

dead-heading on that zone? Is there any sign of antfreeze corrosion around?

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Nate Perkins

I would look very carefully at petroleum contamination in the system. I can't think of a situation where pressure would pop an o-ring out of place unless the valve body had been deformed by freezing or a similar event.