New Backflow Preventer Failed

Hap_Hazzard · February 20

Or should I say, FLOW preventer? Here's the story: I ordered a backflow preventer from Supply House and installed it over the summer. It seemed to work at the time, but when I went to fill the boiler in the fall, I couldn't get water through the autofeeder or the bypass because the backflow preventer was stuck shut. Under pressure, the vent closes, but the outlet doesn't open.

I removed the BFP and took the screen off the inlet to look inside.

It looks like there's some limescale or corrosion in there, but it shouldn't be enough to keep it from working. It was only installed for about four months. I'd really like to take the thing apart and either fix it, if possible, or at least understand why it failed. I really don't want to throw money at a new one only to have it suffer the same fate. Has anyone had any luck getting these things apart? There appears to be a parting line between the flats and the vent port, but, try as I might, I can't unscrew it.

I tried putting it in a vise and screwing a length of ½" pipe into the vent and pulling about as hard as I could without breaking off the pipe, but no joy, so I thought I'd ask for help.

I don't see anything that looks like threadlocker or sealant. I haven't tried applying heat, which is risky with brass and would probably ruin the rubber seals, but if I have to I'll try it.

They wouldn't have used a left-hand thread now would they? Because that would make me mad.

mattmia2 · February 20

I had that happen to the check ball on the outlet of a Claeffi PRV, there is a check built in to the valve for markets where a double check isn't required. The scale attached the plastic ball to the brass seat such that it wouldn't flow water. I strongly suspect it is the additives that our treatment pant adds to keep the water from leaching lead and copper from the piping.

mattmia2 · February 20

as for fixing it, just soak it in some citric acid.

mikedo · February 20

if its a residential bolier with only water in it eliminate it. not really necessasary

mattmia2 · February 20

P2902.5.1 Connections to Boilers

Where chemicals will not be introduced into a boiler, the potable water supply to the boiler shall be protected from the boiler by a backflow preventer with an intermediate atmospheric vent complying with ASSE 1012 or CSA B64.3. Where chemicals will be introduced into a boiler, the potable water supply to the boiler shall be protected from the boiler by an air gap or a reduced pressure principle backflow prevention assembly complying with ASSE 1013, CSA B64.4 or AWWA C511.

ethicalpaul · February 20

I'm kind of afraid mine will seize up too since I don't use it anymore! 😅

hot_rod · February 20

You might go to the manufacturers website to see if they show an exploded view.

Typically that assembly seam goes against a rubber seal, I doubt it would be Loctite-ed together.

The second check generally comes out the other discharge end, you should not need to split it open if the second check is stuck? Push a wood dowel against the first check if it is stuck, without splitting it open.

Warm the large nut with a hair dryer to expand it, it doesn't need to get red hot to losen it.

Screenshot 2025-02-20 at 11.33.01 AM.png

Screenshot 2025-02-20 at 11.33.13 AM.png

EBEBRATT-Ed · February 20

If you manually keep the MU water shut off to a HW boiler there is no need for a backflow preventer. But you would probably have to take the PRV out to pass inspection.

mattmia2 · February 20

https://forum.heatinghelp.com/discussion/comment/1843843#Comment_1843843

You would have to do it with a bucket and a pump or a hose attached to a hose bib with the required level of backflow protection for it to be legal.

hot_rod · February 20

I think if you direct pipe, hard pipe from a potable source to a boiler you need a BFD, to be code compliant.

The question for an inspector is the level of hazard with boiler water. Plain water, chemicals in the water, what if cleaners or chemicals are added, is PG a hazard? What level? Does EG require a different BFD?

Each has a different BFD requirement.

Some inspectors want RPZ, some accept dual checks with vent, some will allow un-vented dual checks.

Lately some areas require the dual checks have test ports! So we will have 4 different BFDs in the catalog to satisfy all the different interpretations across the US and Canada ASSE 1012, 1013, 1024, and ??

The BFD on the boiler protects the building water system. The BFD on the main line protects everyone else that may be connected to the water supply system.

The only way around a BFD on a boiler fill would be a fill tank, isolated form potable water.

Hap_Hazzard · February 20

https://forum.heatinghelp.com/discussion/comment/1843836#Comment_1843836

I'm tempted to get rid of mine too. I soaked it in vinegar and got it working again, but am I going to have to do this every 4 months?

Reading the above requirements, it looks like it might not be code compliant anyway. I use Steamaster, so apparently I need some kind of BFP with an airgap? How does that even work?

ethicalpaul · February 20

by an
air gap
or a reduced pressure principle backflow prevention assembly complying with ASSE 1013, CSA B64.4 or AWWA C511

Hap_Hazzard · February 20

https://forum.heatinghelp.com/discussion/comment/1843894#Comment_1843894

Just as confusing. What are the pros here using for boiler installations with automatic feeders? Anybody have a part number?

ethicalpaul · February 20

I'm not a pro, but my inspector, who is a pro, and was sure to tell me about his 30 years as a pro, and yet didn't think a drop header or pressure control water trap assembly was allowable, liked this one OK:

https://www.supplyhouse.com/Watts-0063190-BBFP-1-2-IPS-Backflow-Preventer

hot_rod · February 20

https://forum.heatinghelp.com/discussion/comment/1843892#Comment_1843892

Are you adding water frequently? On a tight system once filled and air free, water should not need to pass through the BFD.

Granted it should still work properly. I've had ball valves go un-usued for years and the stems break as you try to move them. It's part of the problem with water and valves of any type that are not exercised.

I don't think the code requires a fill valve, add an expansion pig and a LWC

Screenshot 2025-02-20 at 3.51.56 PM.png

ethicalpaul · February 20

Hap Hazzard and I have steam boilers so we are adding water every few weeks probably. I add mine through the skim tapping though so my BFP gets sleepy. I'm planning on skimming soon though, so I'll be able to test it.

Hap_Hazzard · February 20

https://forum.heatinghelp.com/discussion/comment/1843843#Comment_1843843

PRV? What PRV? You mean the 15 psi PRV on the boiler? I thought that was required for inspection.

mattmia2 · February 20

@hot_rod was talking about hot water and a pressure reducing valve, not steam. You could put a boiler drain after the backflow preventer to exercise it. The manual bypass should be after the backflow preventer so that should exercise it. Note that I posted the michigan code. Michigan code tends to be on the stricter side of the middle about protecting water for a lot of reasons. I think some state/city codes allow something less than an RPZ backflow preventer with nontoxic chemicals.

Hap_Hazzard · February 20

https://forum.heatinghelp.com/discussion/comment/1843909#Comment_1843909

I add water maybe once a month, but I feel like I need the autofeeder because the boiler is 40 years old.

https://forum.heatinghelp.com/discussion/comment/1843900#Comment_1843900

That looks basically the same as mine. It also says "Non-Potable Water Applications" in bold.

mattmia2 · February 20

the nonpotable is because it isn't low lead. If you read the code carefully it says that low lead components are only required on lines supplying water for cooking or drinking so the feed to the boiler doesn't need to be low lead according to the code.

ethicalpaul · February 20

It sure does. I don't think it did when I bought it because supplyhouse has a popup window that appears when you try to add it to your cart warning you of such, and there's no way I would have continued past that warning (I am aware of the warning and I dismiss it for my boiler stuff but never for potable applications.).

I'll have to get a potable one

Hap_Hazzard · February 20

https://forum.heatinghelp.com/discussion/comment/1843918#Comment_1843918

Mine doesn't mention it in the product description, but mine's non-potable too. This one's lead-free, which is what's required for potable, but it doesn't mention dual-check.

Hap_Hazzard · February 20

https://forum.heatinghelp.com/discussion/comment/1843917#Comment_1843917

That makes sense. I mean, how could water get into the drinking supply from the backflow preventer, except by backflow, which the backflow preventer prevents.

New Backflow Preventer Failed

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P2902.5.1 Connections to Boilers

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