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PLease help ID this piece as it is leaking

DHome23
DHome23 Member Posts: 4
in THE MAIN WALL

Good Morning all.

I recently replaced a gas power hot water heater (tank) and since the install this piece started to drip water on the side labeled "vent". Pretty sure that prior to installing new hot water tank, this pipe wasn't leaking. It looks like there are 2 ball valves connected to this (1 from hot water tank and 1 going into a water feeder for steam boiler)

Can someone be so kind to help me identify this piece and what purpose it serves and any reason why it would start to leak now.

Many thanks in advance for your help

20240809_083827.jpg

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 24,735

    Looks like a backflow preventor — and dripping from the side labelled "vent" indicates that it isn't working properly. Now why that might be depends on a whole lot of things. It itself may have a problem — most likely the downstream check is not closing properly — but it could be excess pressure on the outlet side or any number of things.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ChrisJ
    ChrisJ Member Posts: 16,289

    Sounds like when they disconnected the water heater lines it caused it to vent.

    If it was mine, I'd find a way to run a good volume of water through it towards the boiler and try and flush it out good.

    If any fresh water ends up added to the boiler make sure you fire it up and boil the water for a bit. Don't let it sit all summer with fresh water.

    Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.

  • Ironman
    Ironman Member Posts: 7,539

    It’s a backflow preventer and it’s probably for a boiler.

    They can leak some after a period of time because mineral deposits build up on the seats of the internal check valves.

    The best thing to do is simply replace it. The vent should be piped down near the floor or to an open drain.

    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • DHome23
    DHome23 Member Posts: 4

    Thanks all for your comments.

    I did take it off and tried to wash it a bit including the washer but it's still leaking.

    If I go ahead and replace it this should stop the leak presumably? If not we have more issues? The part is quite expensive, >$100 on supply house.

    Do you suggest I just take out and replace? Im not sure how to pipe to open drain (there isn't any nearby). Assuming the leak stops, is this necessary?

    Trying to prevent a service call to plumber

    Thanks in advance again

  • mattmia2
    mattmia2 Member Posts: 10,855

    You coudl try cleanign it in citric acid or vinegar and see if that cleans up whatever it son the seat but since it is a safety device, replacement is probably a better option. Did you check the precharge in the dhw expansion tank to make sure there isn't an issue with pressure form the hot water tank?

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,400

    If you don't have a drain for the vent pipe pipe it down to the floor and leave enough room for a small bucket.

    You may be able to take it apart and clean the vacuum breaker. There may also be a rebuild kit which may not be worth the cost of a new one.

  • DHome23
    DHome23 Member Posts: 4

    It seems odd to me that I never had an issue with small leaks or drip prior to the hot water tank swap. Now the comments I'm getting from this group seems to indicate that the dripping is normal. Super confused by this.

    So this begs the question, is this backflow suppose to drip if working properly?

    Thanks!

  • mattmia2
    mattmia2 Member Posts: 10,855
    edited August 13
    https://forum.heatinghelp.com/discussion/comment/1807937#Comment_1807937

    no. If it is leaking one of the checks isn't holding or the pressure on the outlet has become higher than the pressure on the inlet.

    It might let out a little bit of water if you turn off and depressurize the water supply to it but it shouldn't discharge any water under normal conditions.

  • DHome23
    DHome23 Member Posts: 4

    Thank you. I'll replace and see if they fixes issue. Will report back for assistance otherwise.

    Thanks all.

  • ChrisJ
    ChrisJ Member Posts: 16,289
    https://forum.heatinghelp.com/discussion/comment/1807941#Comment_1807941

    This video will probably give you a better understanding of what that thing does.

    https://youtu.be/NQFrSnm2V6U?si=D_9YB5WCNJ0F_LYE

    Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.

  • Derheatmeister
    Derheatmeister Member Posts: 1,580
    https://forum.heatinghelp.com/discussion/comment/1807937#Comment_1807937

    To answer you question…»YES« it is can leak when the pressure is higher on the outlet side i.e on the boiler side… This would also happen if you reduced the pressure on the Domestic side/ waterheater side i.e turned of the water to the home.

    As others have mentioned it could be that the BFP is just aged and in need of replacement..

    This »» COULD«« have be triggert by a reduction in pressure on the inlet of the BFP

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