Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.

water hammer on new gas boiler

alex375alex375 Member Posts: 3
edited January 2020 in Gas Heating
We recently switched from oil to gas and had an IBC DC 20-125 boiler installed. Within days from the initial installation we noticed a loud banging sound when the heat is coming on. The contractor who installed the system came in and identified it as a water hammer and reduced the pressure in the system. For a day or two this appeared to have fixed it but since then the problem reoccurred. The plumber who installed the system is very responsive and has been in multiple times but hasn’t so far been able to pinpoint what the problem is. I was hoping that some of you could have a look at the set up (see pictures) and check if you notice any issues with it.

Thank you for your help.
Alex







Comments

  • JStarJStar Member Posts: 2,752
    The circulator needs to be on the supply, after the air separator. Check the install manual.

    Is the circulator controlled by the boiler, or enabled by the zone valves?
    kcopp
  • alex375alex375 Member Posts: 3
    Thank you!! It looks like you are right that the circulator is on the returning side while the manual does suggest it should be on the supply side. I dont know how to tell how the circulator is controlled.
  • JStarJStar Member Posts: 2,752
    It depends how it's wired, but we can maybe find out another way. Does the circulator ever run when the zone valves are all closed?
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 8,015
    The circulator should be on the supply but that won't stop the banging. I would suspect a zone valve--fighting a check valve in the pump or a wiring issue. If there are check valves in the pump I would remove them. I see no need for them with zone valves
    kcopp
  • clammyclammy Member Posts: 2,603
    Aside from what others have stated ,when does the banging occur at beginning or end of a call for heat ,I think your installer should have added a pressure differential valve between your supply and return piping to prevent your zone pump from dead heading . Personally on my own jobs using zone valves I use a taco zone valve controller and wire my pump off of it ,this way the pump shuts off before the zone valve closes preventing dead heading or use the central heating pump relay in the boiler and install a by pass . I highly doubt boiler water pressure was the issue . I would also make sure the flow is in the right direction I also doubt the location of water feed and spriovent location is that critical weather on return or supply side of your primary secondary for your boiler .your zone valves are on the return side of your system correct ? Peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • clammyclammy Member Posts: 2,603
    A closer look and it may appear that the end switches on the zone valves are jumped ? They should be tied into that taco pump relay not jumped if I see correctly peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • alex375alex375 Member Posts: 3
    edited January 2020
    Thanks for all the suggestions.
    To answer some of the questions (as far as I can tell with my limited knowledge):
    The circulator is controlled by the zone valves.
    The zone valves are on the return side.
    The bang occurs at the beginning of the call for heat when the circulator kicks in. The strength of the bang varies widely from barely perceptible to "the house is shaking". It also doesn't always happen, which makes reproducing it for the installer difficult. We were lucky it happened naturally when he came back the first time.

Leave a Comment

BoldItalicStrikethroughOrdered listUnordered list
Emoji
Image
Align leftAlign centerAlign rightToggle HTML viewToggle full pageToggle lights
Drop image/file

Welcome

It looks like you're new here. If you want to get involved, click one of these buttons!