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Noisy Central Heating System

  • 17-07-2010 07:01PM
    #1
    Max Moment
    Registered Users, Registered Users 2 Posts: 252 ✭✭


    Hi All,

    First time poster!! I would appreciate it if you had any advice on the following: Basically have a closed heating system in a new house with a condensor boiler(2 years old). When the 'boost' or set timer period has ended and cuts out the boiler, there is a loud bang! This has only started happening recently and I have been in the house since new.

    To me it sounds like the heating pipes which run from the boiler in the ceiling and drop in the stud walls are hitting against something when the flow from the boiler stops at the end of the heating cycle? The heating system is zoned:downstairs, upstairs and hot water. This only seems to happen when the down stairs zone is on by itself. When both the upstairs and downstairs zones or water are heating and boiler cuts out at the end of the boost period etc, there is no bang or noise.

    Any help is much appreciated

    Max


Comments

  • #2
    yoshytoshy
    Closed Accounts Posts: 3,305 ✭✭✭yoshytoshy


    Sounds odd ,it could be your pressure reducing valve opening up ,because you have no circuit or pump overrun.

    But it's strange that it's taken so long for it to start happening.

    You'd be better off getting it serviced ,banging sounds are not good for your boiler.


  • #3
    JohnnieK
    Registered Users, Registered Users 2 Posts: 2,526 ✭✭✭JohnnieK


    Dose the noise come from the boiler or the system?


  • #4
    Max Moment
    Registered Users, Registered Users 2 Posts: 252 ✭✭Max Moment


    The boiler is not due another service for a few months but might get it done for peace of mind.

    The noise comes from the pipework I think. Boiler is located in the living room but when it cuts off etc. I can hear the 'bang' when in any of the downstairs rooms. It's like the pipes are loose in the stud walls / ceiling and are hitting against them when the boiler stops? Could the pipes have come away from their supports?


  • #5
    JohnnieK
    Registered Users, Registered Users 2 Posts: 2,526 ✭✭✭JohnnieK


    It sounds like vibrating pipes alright. I dont think a boiler service will fix this and If you get some one from Board Gais they wont do anything for you anyway except charge you (they dont touch the wet side)


  • #6
    Max Moment
    Registered Users, Registered Users 2 Posts: 252 ✭✭Max Moment


    JohnnieK wrote: »
    It sounds like vibrating pipes alright. I dont think a boiler service will fix this and If you get some one from Board Gais they wont do anything for you anyway except charge you (they dont touch the wet side)

    Thanks for the reply Johnnie. Any ideas what is causing this or how to stop it happening? Hopefully it won't involve busting open walls!!!


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  • #7
    JohnnieK
    Registered Users, Registered Users 2 Posts: 2,526 ✭✭✭JohnnieK


    You will probably find that there is one pipe that is the culprit. You will have to do it by process of elimination. Run the boiler as normal and turn off do the boiler first and then each rad in turn listening for the bang. By the way is it a system boiler or heat only boiler. System would have pump expansion vessel built in. Check the hot press too, if the system is split there you can hold pipes to see if the noise stops when you are holding them.


  • #8
    yoshytoshy
    Closed Accounts Posts: 3,305 ✭✭✭yoshytoshy


    When I mentioned a service ,it was more along the lines of getting it checked out and telling you what the problem is.

    Board gais are pretty much useless when it comes to inspecting your complete system.

    I'd be still thinking it's your safety valve ,but it could be a coincidence with something else.


  • #9
    kscobie
    Registered Users, Registered Users 2 Posts: 257 ✭✭kscobie


    Could be the action of a motorised valve closing, and the sudden circulation stop could be the cause, i came across it before


  • #10
    JohnnieK
    Registered Users, Registered Users 2 Posts: 2,526 ✭✭✭JohnnieK


    Is your system fully pressurized or on a semi-sealed system?


  • #11
    davidoco
    Registered Users, Registered Users 2 Posts: 655 ✭✭✭davidoco


    kscobie wrote: »
    Could be the action of a motorised valve closing, and the sudden circulation stop could be the cause, i came across it before

    Agree. OP manually open and lock all the zone valves, run the boost then unset (switch off). I don't think you'll hear the bang. Turn back to auto the zone valves one by one and you should identify the culprit. PS the water should be up to temperature.


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  • #12
    HighlyCooL
    Registered Users, Registered Users 2 Posts: 187 ✭✭HighlyCooL


    davidoco wrote: »
    Agree. OP manually open and lock all the zone valves, run the boost then unset (switch off). I don't think you'll hear the bang. Turn back to auto the zone valves one by one and you should identify the culprit. PS the water should be up to temperature.


    it sounds to me like its just a zone valve is on its way out. i would do as davidoco has said but in sum cases the clock controls the zone valves and the valves control the boiler(5 wire ie. zone valves with the dry contacts in them) in which case the clock will not start the boiler. there is usualy a lever on the valves, all you have to do is push them to open and the boiler will fire. might be a good idea to take the motor off and open the valves by hand and then move the lever.


  • #13
    Max Moment
    Registered Users, Registered Users 2 Posts: 252 ✭✭Max Moment


    JohnnieK wrote: »
    You will probably find that there is one pipe that is the culprit. You will have to do it by process of elimination. Run the boiler as normal and turn off do the boiler first and then each rad in turn listening for the bang. By the way is it a system boiler or heat only boiler. System would have pump expansion vessel built in. Check the hot press too, if the system is split there you can hold pipes to see if the noise stops when you are holding them.

    I tried running the boiler and turning off each rad in turn as you described but unfortunately I could not tell where the noise was coming from for definite. By a system boiler do you mean does it provide heat and hot water? Yes it does. Could see the pipe which has the down stairs zone motorised valve moving down slightly when the heat goes off though and this valve closes?


    JohnnieK wrote: »
    Is your system fully pressurized or on a semi-sealed system?
    It is fully pressureised AFAIK. How would I tell the difference? system is topped up via a main filling loop in the hot press if this helps.
    davidoco wrote: »
    Agree. OP manually open and lock all the zone valves, run the boost then unset (switch off). I don't think you'll hear the bang. Turn back to auto the zone valves one by one and you should identify the culprit. PS the water should be up to temperature.

    I think you might be on to something here davidoco. I tried this and low and behold no bang when i manually opened the valves and switched off boiler. I turned the upstairs and hot water back to auto but there was no bang but when i turned the downstairs zone back to auto, I could hear the bang as usual and could see the pipe which the valve was on shunting down a few mm.
    HighlyCooL wrote: »
    it sounds to me like its just a zone valve is on its way out. i would do as davidoco has said but in sum cases the clock controls the zone valves and the valves control the boiler(5 wire ie. zone valves with the dry contacts in them) in which case the clock will not start the boiler. there is usualy a lever on the valves, all you have to do is push them to open and the boiler will fire. might be a good idea to take the motor off and open the valves by hand and then move the lever.
    Do you think this motorised valve has had it and replacing this will solve the problem? is it an easy job to do or is it one for the experts? I am fairly confident at basic plumbing but haven't done anything like this before.

    Thanks again all for your help


  • #14
    Max Moment
    Registered Users, Registered Users 2 Posts: 252 ✭✭Max Moment


    'Bump'!!!

    Just wondering if anyone can advise on my last post? Do you think the motorised valve is at fault here? Is it easily replaced? Where is the best place to buy one?


  • #15
    kscobie
    Registered Users, Registered Users 2 Posts: 257 ✭✭kscobie


    yeah, it depends on the make, danfoss,myson, honeywell etc would have a removable head, or actuator to give its proper name.You wont need to drain the heating system if it does, BUT BE CAREFUL , cheaper makes like orki cannot be replaced and will leak through;)


  • #16
    Meter
    Closed Accounts Posts: 3 ✭Meter


    Hi all,

    I live in a studio and the noise of the old APT timer during the night is driving me crazy.

    How can I stop the noise without to switch off the timer??? Any idea??

    Thanks :)


  • #17
    HighlyCooL
    Registered Users, Registered Users 2 Posts: 187 ✭✭HighlyCooL


    A digital time clock to a contactor. That is presuming it's electric water heating


  • #18
    kscobie
    Registered Users, Registered Users 2 Posts: 257 ✭✭kscobie


    easist option is to replace the timer, this would be common enough problem when they are in for a few years


  • #19
    gaskman
    Registered Users, Registered Users 2 Posts: 12 ✭gaskman


    what make of boiler have you got and have you got TRV's on your rads? some boilers have a built in By-pass or a auto By-pass on the pipe work and can make a banging noise as the trvs close down.if so just reduce your pump speed .You can find your pump in side your system boiler or in most cases over the boiler if its a heat only boiler (open vented).:o


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