Heating boiler backflow preventer valves (BBFP) FAQs.

This article series describes backflow preventers used on heating boilers including their function, location or placement, and their troubleshooting and repair of leaks or other problems.

Heating Boiler Backflow Preventer Valves [BBPF] FAQs

These questions and answers about boiler backflow preventers were posted originally

at BACKFLOW PREVENTER VALVE, HEATING SYS - you will want to review the explanation and types of valves and diagnostic suggestions there.

Heating boiler backflow preventer valves protect public water mains as well as private building water piping from heating system water contaminants.

Are backflow preventer valves used on both hot water and steam heat boilers?

Would you use a backflow preventer on both a hot water and steam heating systems? On 2019-06-11 by Tucker

by (mod) - Yes

Yes, in that it would make sense if we are talking about at the pressure regulator that feeds water to the system.

 

My boiler's backflow valve is leaking at the relief port

My back flow valve on the boiler is constantly leaking ....currently have no running around water or pressure. Well pump pressure at zero. Any thoughts? On 2018-05-09 by Brian

Reply by (mod) -

I am guessing that your backflow valve is leaking at the relief port, not one of its plumbing connections.

If that's so, and IF your piping system never suffers from water hammer (that can cause such valves to leak), THEN debris could have jammed the valve's internal closure port - I would replace the valve.

Why is the boiler backflow / check valve vent leaking?

Why is water backing up from the boiler supply feed and leaking out of the dual check valve vent On 2015-12-24 by Sonny

Reply by (mod) -

Sonny

I expect your service tech will look for a failing or debris-clogged check valve, or less likely an overpressure condition due to a water feed problem or other overpressure cause.

Taco Flo-Chek #219 valve stopped leaking after I fooled with it

New two zone forced hot water heating system has had Ttaco #219 flo-chek replaced on one zone and new valve is leaking after a couple of weeks allowing hot water into zone (first seemed to last a few weeks also) taco said to clean the seat maybe it got solder or flux on it, can you describe the necessary steps for this job
Thanks curt

Later: Opened and closed thumb screw a couple of times and it's working correctly at this time On 2017-02-02 by Curt

Backflow preventer leaking after we turned off building water to do a repair

2 days ago we had to turn off the water in our home to perform a plumbing repair. We turned the water back on without incident.

A little over 30 hours later, the backflow preventer is now leaking, probably releasing a full bucket of water and still going.

Is this normal or should we get our plumber over to look at it? On 2015-09-15 by Michelle

by (mod) -

It sounds as if there is over pressure, a water hammer problem, or a failed backflow preventer - maybe debris clogged. Yes call the plumber.

by Michelle

Thanks! Will do

Can a backflow preventer valve prevent water from entering the boiler?

Can a faulty backflow prevention valve block water from entering the feeder valve and subsequently, into the boiler?

No water is flowing through the feeder valve after we bled the baseboard heaters. On 2016-01-02 by Rose

Reply by (mod) -

Rose,

I have not found reports of a failure of a backflow preventer to pass water on through to the system except in cases where it was installed backwards, but I suppose it's possible.

When I read manufacturer's description of backflow preventer valve failures and testing procedures, the discussion attends water discharge from a relief valve port on the backflow preventer valve and it attends failure of the first or second check valve components that reduce pressure across the valve.

The effect of a failure in the check valves would be an increase in system pressure on the downstream or boiler side of the valve, not a failure to pass water.

There are of course various models and applications for backflow preventers that include other features such as a backflow preventer designed to always pass water at the first few psi of demand to assure water feed to a fire sprinkler system, and SVB versions of backflow preventers that include a shutoff feature; none of these are likely to be found on most residential h eating systems.

So I'd start by investigating the condition of the water feeder valve, or first testing its pressure bypass lever feature if your valve includes that component.

 

Can I replace my 1/2 in. backflow valve with 3/4 backflow valve

can I replace my 1/2 in. backflow valve with 3/4 backflow valve on my hot water furnace ? On 2017-06-21 by ron

Reply by (mod) -

Yes, sure.

Can I replace the backflow preventer without draining the whole boiler system?

Can I change my back flow preventer on my boiler without draining the whole system ? HANKS On 2015-07-31 by clem zahrobsky

by (mod) -

You can if there is a shutoff valve between boiler and the water supply.

by Clem

Thanks for the prompt reply. yes there is a shut off valve before the back flow preventer and the water pressure reducer is after the BFP

Reply by (mod) -

You're good to go.

Can Heavy Rain cause municipal water pressure to fall enough to let the boiler water back-feed into the water pipes?

Can a heavy rain drop municipal water supply pressure down enough to draw water/air back from boiler water to house supply water when there is no or faulty check valve?

Can addition of above check valve solve such a problem if it is possible? I get air in my pipes seemingly only after heavy rains. This website seems to be my only hope. Boiler system frequently air bound,

No cold sections but a lot of water flowing sounds. On 2014-08-08 02:22:22.008670 by Christina

by (mod) - no but yes

Christina

I've not come across research nor field experience that associates heavy rainfall with falling municipal water pressure, though I could SPECULATE that flooding could of course impact pumps, wells, or water delivery systems in general.

But YES, if municipal water pressure falls below the boiler's internal water pressure (typically between 12 psi and just under 30 psi) AND if there is no backflow preventer, water from the boiler might back-feed into the building water supply piping if there is no backflow preventer valve installed and if the water feeder valve to the boiler is open.

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Continue reading at BACKFLOW PREVENTER VALVE, HEATING SYS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

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• CHECK VALVES, WATER SUPPLY, DRAINS, PUMPS
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  • BACKFLOW PREVENTER VALVES on HEATING BOILERS
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