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banging pipes that wake the dead - please help!

51505150 Member Posts: 2
I had a Weil-Mclain Gold CGa Furnace with Erie zone valves installed. The heating in our house is hot water baseboards. Ever since the new furnace was installed, when the heat comes on or turns off, there is a loud bang in the pipes. It's not 100% consistent, but it happens quite often.

We had the furnace company come back to look at the problem. They only suggested adding padding around the pipes but most of the pipes are behind sheetrock.

It sounds way too loud to be air in the pipes and it didn't happen with the old furnace, so something about the new furnace or piping in the furnace room must different enough to be causing this problem.

Have any other suggestions?


  • kcoppkcopp Member Posts: 2,744
    its the way....

    they installed the zone valves. Either they installed them backwards and/or they ahve them too close to the cirulator. Whaen both are open and one closes you get a problem called hydraulic jump. You could move the zone valves to the opposite side or installa diff. circulator... a grundfos 15-55 alpha would be ideal.
  • Mark EathertonMark Eatherton Member Posts: 5,582

    This person contact me off line and I suggested he come here to post to see if anyone can help him.

    See attached pictures. Nice clean installation, but....

    I'll let others chime in and see if they pick up on what I picked up on.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • Brad WhiteBrad White Member Posts: 2,393
    edited February 2011
    Pop Quiz

    1) Hard to tell where the E-Tank connects but it seems to be at the circulator discharge, not the inlet.

    2) CW make-up seems to enter directly to the boiler. Potential for thermal shock if a large influx without dilution.

    3) I believe the air separator is omni-directional so that vent location should not be an issue.

    4) Gas pipe apparently shares the same drop as the DHWH (but this is hard to tell). If so, there is no apparent isolation gas cock visible for the DHWH, not sure about the boiler or if they share a common gas cock up high.

    That is what I see. What did you see, Mark?
    "If you do not know the answer, say, "I do not know the answer", and you will be right!"

    -Ernie White, my Dad
  • Steve WhitbeckSteve Whitbeck Member Posts: 669
    edited February 2011

    The only thing I can see that could cause the noise would be the zone valves. I don't sell Erie valves so I can't tell if they are properly installed ( I also couldn't find a web site that showed a picture of flow direction.) I would say the valves are in backwards.

    I sell Honeywell valves because you can remove one spring if they close too fast.

    If the valves are installed with the flow in the right direction then a pressure differential bypass valve would help a LOT.
  • Mark EathertonMark Eatherton Member Posts: 5,582
    Good eye Brad...

    That is what I saw too. I recommended to the HO that he observe the fluid pressure gage and see if it jumps when the BANG occurs. If it doesn't, it is probably an expansive pipe, tight hole issue. If it does JUMP when it BANGS, and the temperature at that point is high, then it is probably a negative pressure induced steam bang, and relocating the pump and zone valves will correct that deficiency.

    Oddly enough, their photographs in their I&O manual show the circ on the boiler supply, but if you look at the I&O manuals detailed piping drawings, it show the circulator on the boiler supply as the "alternate" location.

    When are the boiler manufacturers who are stuck in the old ways of doing things going to wake up and smell the coffee?

    Just thinking out loud here...

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • Big EdBig Ed Member Posts: 863
    Zone Valve

    I am not an Erie user either ..I down loaded a tach sheet .. Looks like it may be backwards ... Seem like the lever on top it would be closing with the flow... Check the arrows on the zone valve to double check , it should be pointing up.....

    But it was mentioned noise on start up and shut down ??
    I have enough experience to know , that I dont know it all
  • SirlimeySirlimey Member Posts: 13
    Zone valve

    Sounds like you have a boiler added to an old system. ie pipes that where very sparingly clipped and secured. Erie zone valves are a fast acting zone valve that turn on and off fast. As opposed to most that are a lot slower. At a guess I can only guess you have a hammer problem caused by the zone valve shutting or opening to quick. This is just a shot in dark.
  • Steve WhitbeckSteve Whitbeck Member Posts: 669

    The easiest way to test for water hammer would be to turn up both thermostats and then turn off one and see if it bangs. Then leave that one on and try the other. If only one causes a bang than that is probably the short loop and the only solution would be to install a Honeywell valve with one spring disconnected to slow down the valve closure. Don't remove the spring completely since you may need to reconnect it as the valve gets older and needs both springs to close properly.
  • SirlimeySirlimey Member Posts: 13

    Can you post a pic of instilation
  • SirlimeySirlimey Member Posts: 13

    Can you post a pic of instilation
  • Big EdBig Ed Member Posts: 863

    ... already posted a few photos.
    I have enough experience to know , that I dont know it all
  • billbill Member Posts: 429
    What if?...

    that air elimination tapping in back of the supply were not used as the water make up spot? Seems like that nice spirovent is being insulted.
  • EricEric Member Posts: 261
    edited February 2011
    process of elimination..

    If the sound is hammer, it would still occur even after the system has been running for a while and hot. As mentioned, I'd run the system to get it up to temp, shut off the zones one at a time, and turn that zone back on while the other zone still on. All the piping will still be hot and banging would not be from thermal expansion at that point.

    I am not a fan of the location of the low water cut off. I like installing them on the vertical riser pipe (between the pump and that black tee- if on the return) (in the flow) instead of the end of that header. What would stop that probe from becoming blocked with sediment after some time where it's at in that picture?
  • marcelmarcel Member Posts: 1
    banging pipes

    We in stalled a CGa3 recently and I noticed that it made quiet a bit of noise when the gas valve turned of and on. After expierementing I found that the gas valve is much louder than the old boilers gas valve. Since the valve is hard piped to the gas supply in the basement that noise radiates along the gas lines and I hear this up stairs and its anoying. The sound also travels to the fireplace pipe that supplies the gas log set. What I did to correct the problem was I used a gas flex line from the gas valve to the gas line so the noise is prevented from radiating along the solid pipe. Worked like a charm! Hopefully this will solve your problem also. Good Luck.
  • nicholas bonham-carternicholas bonham-carter Member Posts: 6,535
    edited November 2012
    Follow up

    Too bad we don't get a follow up on these problems, and their solutions. I am sure that is because the Heavy-Hitters on this old thread nailed the solution perfectly. I miss Brad Whites remarks- can he be enticed to return again?--NBC

    Maybe this noise could be used to revive some of the Dead Men.
  • billtwocasebilltwocase Member Posts: 2,385
    my guess

    I would say the LWCO. That would function best on the supply. Z/V could be backwards, but thinking that when the circ starts, could give the LWCO a false sense of low water.
  • tim smithtim smith Member Posts: 2,226
    re: banging

    I am betting on zone valves in reverse.  Could not zoom in enough to see but that would be my first bet.  Other very good option would be boiler up to temp and one zone running, 2nd zone been off for a while, opens up gets slammed with hot water and pipes move like  you know what.
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