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Boiler temp too high? Causing loud banging?

nikibooks
nikibooks Member Posts: 44
edited January 2017 in Gas Heating
I have a Lochnivar plus Knight wall mount boiler control module. It provides hot water to two hydronic radiant floor loops and the exchanger in the domestic hot water tank. It was working well for the first couple of years. Now the only defect is this: for a couple of years it is making loud explosive bangs at moments I can't predict. I recently sat next to it for 5 hours waiting in vain for a bang so I could see what the control screen said. Within a day it made 3 or 4 bangs in a half hour stretch while I was elsewhere in the house.
I called in the installing business but found out my installer was no longer working there, and the new person seemed to find nothing wrong. That business is not functioning any longer. I have the service manual, but of course user access to the settings is almost nonexistent; it allows only installer access.
Banging like that feels like something too hot encountering cold. This phenomenon is way worse in winter. What should I do?
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Comments

  • Harvey Ramer
    Harvey Ramer Member Posts: 2,217
    Can you take some pictures of your system and post them?
  • nikibooks
    nikibooks Member Posts: 44
    Let's see if this photo (a pano-combo) is good enough.

  • nikibooks
    nikibooks Member Posts: 44
    Trying to load image.
  • nikibooks
    nikibooks Member Posts: 44
    Is there a size limit?

  • Ironman
    Ironman Member Posts: 6,563
    edited January 2017
    It could be any number of things. The first that come to mind are delayed ignition or water flashing to steam in the heat exchanger because of loss of flow.

    I'd recommend that you get a COMPETENT pro familiar with mod/con boilers.

    Have you tried the contractor locate on site?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • nikibooks
    nikibooks Member Posts: 44
    It just banged a minute ago. I ran in there and looked and it was not cycling the hot water tank. It was doing the radiant floor. That busted a theory of mine.

    Do you mean a contractor locator within this website? I will look.
  • nikibooks
    nikibooks Member Posts: 44
    I guess this is not a site for the Pacific Northwest. No contractors.
  • nikibooks
    nikibooks Member Posts: 44
    Ironman/Bob, I would love to toss around some theories, because when a service man did come, he said the ignitor and the flame sensor were working well. The condition of the inside was good. The noise didn't happen, of course.

    If I could figure out the name of the installer, Mike something, I would try to find out where he went. He would know, because he did the whole thing in 2013.

    The bangs are very loud and explosive. I think the last one was at the end of the cycle, because the circulator went quiet as I walked in the door and there were no calls for heat.
  • JUGHNE
    JUGHNE Member Posts: 8,949
    Did the last service man open the heat exchanger? I'm assuming this is a water tube HEX.....someone else here can say.

    I have had this type of heat exchanger do delayed ignition or flame out on low fire and delayed relight from hot burner surface.

    Simply needed cleaning.
  • gschallert
    gschallert Member Posts: 170
    nikibooks said:

    I guess this is not a site for the Pacific Northwest. No contractors.

    Have you tried finding an alternative service company through Lochinvar? http://www.lochinvar.com/support/ContractorLocator.aspx

    Was the last time anything was done 2013? At the least it should be inspected and cleaned before every heating season.
    Steve Minnich
  • nikibooks
    nikibooks Member Posts: 44
    The inspection was in 2016. The install was 2013.
    I will use lochinvar site next.
  • lchmb
    lchmb Member Posts: 2,997
    edited January 2017
    was any work done to it at the time it started baging?? Replace a circulator, a zone valve? Boiler low on water and added some? Anything that changed prior to the banging? Sounds like an issue with the zone valves...something hammering on them when they open..
  • nikibooks
    nikibooks Member Posts: 44
    Could hammering sound like a singular, loud explosion? I've sat and watched hours of operation waiting for it to happen, seeing all manner of demand and circulation. It is seemingly random.

    I did find a business listed on the Lochinvar page and will call them Monday.
  • Formerly
    Formerly Member Posts: 78
    any word on an outcome?
  • nikibooks
    nikibooks Member Posts: 44
    Oh, man. Boiler still bangs. Haven't called serviceman yet because life got in the way. First I had Meniere's attack (weeks of recovery required). Then Husband had surprise open heart surgery (still in ICU). Life can sure turn upside down. But I'll do it eventually.
  • Zman
    Zman Member Posts: 6,989
    I agree with iron mans line of thinking.

    A quick thing to check would be something plugging up your venting pipes. There should have some sort of screen to prevent rodents from entering. Look at the place where the white pipes on the top of the boiler go outside.

    I don't see any air elimination device in your picture. If there is not one the air may be getting trapped in the upper part of the boiler. I think that could cause a noise like that.

    If you follow the copper pipe that goes to the top of the boiler there should be a valve with a lever on it. Lift the lever and see if air comes out, keep open until you get water.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • nikibooks
    nikibooks Member Posts: 44
    Lifted lever, no air came out. No water came out either. The lever (with force) went up and over 180 degrees. I put it back to original position. Did that explain anything?

    Venting pipes go up through the roof, in a special in-and-out-through-the-same cylinder device. Screen is over the top. I will inspect it when I can.

    Thank you for thinking further about this.
  • j a_2
    j a_2 Member Posts: 1,796
    Can you access the settings.....you need to do that first....then we could help guide you thru them....if possible post a video with sound...when it's happening......The exhaust pipe appears discolored, but I can't really tell....Post a close up of it if you can...
  • Zman
    Zman Member Posts: 6,989
    You may have no system pressure or a bad valve. Either is a dangerous operating condition.
    The other end of that copper pipe should be open to air.
    What does the round gauge in the middle of the picture read?
    The noises you are describing are not normal.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • nikibooks
    nikibooks Member Posts: 44
    That pipe is open to the air only via pressure relief lever, No escaping air comes out the top of the system when I lift the lever.

    Pressure is about 16 psi. I can post a snapshot of the gauge...if you want.
  • nikibooks
    nikibooks Member Posts: 44
    pressure 40ish feet H2O
  • nikibooks
    nikibooks Member Posts: 44

  • nikibooks
    nikibooks Member Posts: 44

  • nikibooks
    nikibooks Member Posts: 44
    As for rodents--not in this roof top situation. But could a blockage build up in venting pipes from slow pile-up of Douglas Fir needles going through the screen? The pipe faces up not sideways. House is surrounded with big trees.
  • nikibooks
    nikibooks Member Posts: 44
    Pressure is lower than shown in photo. Just now. more like 25 or 30 psi not 40. Does it change during operations?
  • JUGHNE
    JUGHNE Member Posts: 8,949
    When you lift the lever on the pressure relief valve on the top of the boiler you should get a good flow of water out the end of the pipe. You can hear it and see it......the pressure should drop and recover back to where it was.
    Do this with the power off and boiler cool. That safety function will operate with out power....all about water pressure.

    This is a very serious issue if no water comes out.
    Zman
  • JUGHNE
    JUGHNE Member Posts: 8,949
    Are you reading the inner blue scale......the 0 to 75 PSI?
  • nikibooks
    nikibooks Member Posts: 44
    Jug, that pressure relief valve on the top that I photographed doesn't have an end. It is part of the looping copper pipes. So water may be flowing but it's not visible.
  • nikibooks
    nikibooks Member Posts: 44
    About the psi reading on the gauge-- I did make a typo. I'm still at ICU and can't look at it for a few more hours. What pressure is too little? 16? 10?
  • Zman
    Zman Member Posts: 6,989
    OK, super important! Where does the copper pipe attached to valve in your last photo go?
    It must vent to air or you have a very serious safety issue. I am not trying to be dramatic but that pipe and valve are the only thing that keeps the boiler from exploding. Please follow that pipe and report back.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • JharrisSeattle
    JharrisSeattle Member Posts: 26
    The relief must go to the atmosphere. I can see from the first photo where it comes off the top of the boiler then tees in with the rp airgap. As far as the banging, we had a odd one recently on a TT that was intermittent loud banging caused by a hole in the burner. The odd thing was the combustion analysis yielded perfect o2,co2 results in low and high fire with <100 ppm co
  • Zman
    Zman Member Posts: 6,989
    Good eye on the rp airgap. Hopefully it goes to a drain and not outside where it could freeze.
    I would pill the lever up again until you hear either air or water. Hold it until you hear water.
    Your problem is likely either air hammering inside the boiler or a boiler combustion issue.
    From your description of the timing, and the fact you don't seem to have any air eliminator, I am guessing air.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • nikibooks
    nikibooks Member Posts: 44
    Zman, thank you. I shouldn't have been sloppy when I said it looped back. It has an air vent and then a water dump through the floor which I wouldn't see or hear. See picture. As for freezing, it rarely freezes in the Willamette Valley of Oregon, but it does do so and has done so on occasion. It is 35 degrees F now. Does water drip out often and therefore freeze into a dam, or only go out in a pressure relief situation?

  • nikibooks
    nikibooks Member Posts: 44
    In your understanding, if needles have entered the screen and are messing with the dual vent could that make these random explosions happen? Poor venting, that is.
  • nikibooks
    nikibooks Member Posts: 44
    j a, thank you

    you asked:
    Can you access the settings.....YES I CAN BUT NOT THE INSTALLER STUFF<> JUST THE HOMEOWNER SETTINGS you need to do that first....then we could help guide you thru them....if possible post a video with sound...NEVER CAN CAPTURE THE SOUND BECAUSE IT'S SO RARE AND SUDDEN. when it's happening......The exhaust pipe appears discolored, but I can't really tell....Post a close up of it if you can...CLOSE UP OF EXHAUST COMING.
  • nikibooks
    nikibooks Member Posts: 44
    Exhaust/Venting details: Stood on a stepstool to see and I'm suspecting that the venting is compromised, and poorly installed judging by the water staining on the ceiling. But the staining you see on the pipe itself is because of the purple PVC glue the man used. It's ugly but looked that way from day 1. I was going to spray paint it white to cover it.





  • Zman
    Zman Member Posts: 6,989
    It looks like you have a manufactured concentric vent on the roof. Unless it is actually covered up, I doubt it is plugged up with needles.
    I would lift the lever on the top left of the boiler and listen carefully. It may pass air quietly at first, then water. You will be able to hear the water.
    Take a look around you system and see if you can find anything that looks like these http://www.supplyhouse.com/Air-Eliminators-310000
    Without an air eliminator, air will get trapped in the top of the boiler and can make the noise you are describing.

    That boiler should also have an air bleed valve inside the jacket in the top let corner. Lifting the T&p lever as described will accomplish the same thing.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • nikibooks
    nikibooks Member Posts: 44
    Yes, Air eliminator is installed just under the ceiling of the case. See photo. I lifted lever again and heard the water move out. I didn't do that on a cold boiler. Heating and hot water continuing.
    Haven't heard explosion more recently than a couple of days ago. But I keep spending time out of the house.
  • nikibooks
    nikibooks Member Posts: 44
    Hmm. today it won't upload the photo. Anyway, the air eliminator does exists within the jacket.
  • Zman
    Zman Member Posts: 6,989
    Post the picture when you get a chance. The ones I have worked on just have a bleed valve
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein