Leaking Backflow Valve

Norm Harvey

You could try installing a ballvalve after the PRV to seperate the BFV and PRV from the boiler. It makes replacing either a snap also.

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Neil_5

Gas Boiler with Backflow valve

My set up: 60 PSI city water in, to a ball valve, then to the back flow valve follow by the PRV then boiler. System has been tight at 17 PSI all season, no sign of leaks. The ball valve feeding the system is off. Tonight I noticed the vent on the backflow started to drip about 1/2 gallon of water, as a result the system pressure dropped to 2 PSI.

I open the water feed valve and in 1 sec the system pressure came back to 15 PSI.

Why would the backflow valve leak? The expansion tank is not ruptured and set at 15 PSI.

Any suggestions welcome.

Thanks,
Neil

lee_7

Where is the automatic fll valve located??? I have heard that if no inlet side pressure on valve, Valve will loose pressure.

mikea23

I have had leaks with the small 9D backflow valves also I normally put the turn off after the backflow and turn it off. there is also a backflow without a vent not sure if it meets code in your area

Neil_5

Location

City Water, ball valve, BFV, PRV into boiler.

The valve reads 1/2" BFV Preventer. No M/N.

I have the ball valve off all the time that feeds the system, so one side of the BFV is at low pressure and the other side sees the boiler pressure.

I am in LI NY, Nassau County.

Neil

mikea23

Neil

Thats the problem the the space between the backflow and the valve that small space the water is expanding has no place to go but out the vent it is traped try moving the valve to the other side or leave the feed on so the ex tank can absorb. I am in Suffolk County and never had a problem with the Backflow with no vent on inspection but keep the paper work incase they ask for ratings
Mike A

Unknown

those backflow are

Major craploa... More trouble than they worth.....

mikea23

They sure are but they are code
I did a large radiant system and piped the feed with a wash mashine hose purged it and took the hose off. The inspector failed it I was like its not hooked up to the domestic water why do i need a backflow. he said all boilers need them.

Neil_5

Solution

Does the valve need cleaning, or replaced with a vent free unit? Why need a vent, why not a one way valve that separate the domestic from boiler?

I turned on the supply valve and no more leaks, but I prefer to have it off as I have a LWCO installed and my system is tight as well.

Welcome all suggestions and feedback.
Neil

Dave Yates (GrandPAH)_1

pressure issue causes leakage

RPZ BFP will "leak" if inlet side pressure drops off and falls below outlet side (trapped) fluid pressure. Can also occur if a temporary drop in pressure occurs on the inlet side (with all valves open). Dishwashers, washing machines and flush valves can cause a drop-spike water-hammer condition that will drive outlet side pressures up to trap a higher pressure or inlet side to fall below outlet pressure. In cases where the RPZ is constant-duty with valves left open, a soft-seated check valve placed in-line prior to the RPZ will stabilize the "inlet zone" pressure and stop the problem.

Steverino

RPZ

Dave, you mention a soft seated check prior the the RPZ. What if only a Watts "9D" was required, would you suggest the check valve in the same problem existed?

Dave Yates (GrandPAH)_1

yes

The 1/2" soft-seated spring-loaded checks are fairly inexpensive. You'll need to keep the inlet side water turned on.

Neil_5

Dave

I have the water feed line off, so that end is actually cut off from the supply and the cold water expansion tank. I prefer to have the water feed valve close off since a LWCO is installed.

I never had a leaking vent before, but I can see the diff pressure from the supply side to the boiler side.

The boiler expansion tank is functioning well.

Neil

Neil_5

Picture of System

Neil_5

Picture of System

Bob Gagnon plumbing and heating

I had a watts 9D

open full blast from the vent this past summer. Suprisingly another plumber I know had a different brand backflow preventer,p782yL recently do the same thing. Bob Gagnon

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Norm Harvey

Im just playing around,..

But I notice the rainbow of wire zip ties. With some planning you could have used red for supply piping, blue for return, and yellow for the tt wires along the gas line.

Would be a neat little system.





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oil-2-4-6-gas

i've had a few new 1's do the same thing the 9d's --i'm thinking thermal expansion - city water--ball valve--backflow--PRV --then system the pipe between the backflow and the PRV inlet extra pressure has no where to go except out of the vent ----someone might need to develop a small expansion tank for this ----

Unknown

Nassau County

Change it to a ventless backflow preventer . That is all we use in Nassau and Suffolk , and the inspectors haven't given us grief for using them .

I'm suprised we don't see more ventless backflows . Code issue ? We had nothing but problems with the 9-D .

big willy

prvs' check

so if i am under standing right the valve that is off normaly is between the city water supply and the backflow. if thats right and the back flow leaked my thought is were did the water come from. All the prv valves that I have used will check flow. So if the backflow leaked and the valve upstream of it is off and solid then I would think that the prv is letting system water back up into the backflow. A backflow with slight presure downstream and no presure upstream will leak from the vent. I think the only way to tell would be to break the line between the backflow and the prv with the system under pressure and the city water supply valve off.

Neil_5

You are right

In the picture just at the top is a ball valve that closes off the city water from the system. As the vent leaks, the pressure in the boiler drops. So we can assume that the water is comming from the boiler thru the PRV.

Now is PRV suupose to act as a one way? if so why have a BFV when a PRV is installed?

Thanks for all the thoughts and suggestion.
Neil

Neil_5

At Installation

In Sep 04, this is what the co used. I will switch to a ventless unit.

How about plugging/cap the vent outlet? Wouldn't this now be like a ventless system?

Ron, thanks for the suggestion regarding the code.

Neil

Neil_5

Time

I hear ya

Time especially with a new kid that just arrived, but I agree that would be neat.

Here is a shot of the boiler room for kicks.

Neil

Norm Harvey

Is that foam insulating board around the electric service, and does it go the entire perimeter of the foundation?

Ive been wanting to do that in my house but havent got around to it,.. the foil side out has a very nice look to it.

And congratulations on the new arrival!

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Plumdog_2

Backflo preventors

Everybody hates backflow preventors; but they serve a good cause and goshdarnit; they should be given a chance, and a second chance, and soforth. Your boiler has some pressure in it, and if the water pressure to your house was to fall to zero for some reason (a broken water main, for example) the boiler "water" (or treatment or glycol or rank sludge) will migrate into the potable water supply without a backflow preventor on line. Of course you can seperate the two systems, and recent thinking and insurance considerations make this a viable option. But when the pressure gets back on line, that sludge and boiler treatment may have siphoned down the street a ways, where it might comne out in the drinking fountain at your child's school. So just take it apart and clean it, in the case of the 9D, or get a repair kit, or just replace it. They aren't that expensive.

Neil_5

Foam

I rubber seal the entire basement walls, then apply the foam insulations with the foil side to the condition side. Around the panel and boiler remained like that, the rest of the basement and laundry room got framed out with R13 and drywall. I know, with a simple candle the basement can now reach 72 deg

Thanks,
Neil