New central heating - gurgling & running water noises

Discussion in 'Plumbing and Central Heating' started by dslawton, 18 Nov 2008.

  1. dslawton

    dslawton

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    Hi all,

    I have a query that may or may not be a major problem but I'd very much appreciate some expert advice to be sure.

    I recently had my central heating boiler replaced. As it was previously an old gravity fed system it was also converted to fully pumped with the pump and electrics moved upstairs to the airing cupboard. Also had thermostatic values fitted to all rads except for bathrooms and hallway, where the wireless room thermostat is sited.

    Some extra info :
    • New boiler is a Potterton Promax HE Plus condensing boiler, fitted downstairs in kitchen (same site as old boiler)
    • Boiler thermostat set to almost max
    • Hot water tank stat set to 60 deg
    • Motorised 2-way valves fitted on each of radiator and hot water circuits below pump in airing cupboard
    • Pump speed on max (engineer said to leave this way)
    • Gate valve in between motorised valve and hot water tank (turned about half way on/off)
    • Heating system is microbore (house is late 70's build) with rad feed pipes under floorboards upstairs and in concrete floor downstairs
    • 6 rads upstairs 5 downstairs
    • System had full flush prior to new boiler install

    First of all the good news. The effectiveness of both the central heating and the hot water is excellent. Certainly radiators are much hotter and heat up much more quickly than with the old system. All radiators get hot and there aren't any cold spots. Hot water also fine. So I have no complaints with this at all.

    My query is with the noises, of which there a few which may or may not be related :

    1. When the boiler fires upon timer coming on and request for heat from the radiators, there is what I can best describe as a gushing and gurgling of water from all around the pump area. Now I know the pump will obviously make a noise when it starts up but it seems to be all around the piping gurgling for quite probably 10 seconds. Can be quite loud. No banging just gurgling and glugging. Noticeably worse on initial morning start up from cold when the odd glugging sounds can go on for half hour or so. Eventually goes away once warmed up but also then gurgles, albeit less, when boiler kicks in again when further request for heat.

    2. Trickling water sound down the radiator hot feed pipe from pump leading to downstairs radiators. Can get quite loud (like tap running). Only makes noise when downstairs rads are warming up (i.e. no noise until upstairs rads are hot and downstairs rads then get heat. No noise when heating switches off)

    3. Water trickling sound coming from pipes going in/out boiler, again like a tap running slowly

    I only get the sounds when the heating circuit is running (i.e. it's fine when just hot water cirtcuit)

    So my obvious first thought was air in rad cirtcuit so bled all the rads. Which were fine. Tried isolating to a single rad and bleeding. No air all fine. Bled pump by loosening screw in centre, also fine. Also checked header tank in loft to make sure it had water and water was on. Fine again. I also tried different pump speed settings, no change.

    So I called the company who fitted it, who have been helpful and came out to inspect right away. They checked various things but pretty much said its working fine and that the noises would eventually go away.

    I guess my expectation was for a system that was quieter than the old one rather than noisier, but this isn't the case.

    Any advice very much appreciated. Thanks!
     
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  3. Steve69the69Gas

    Steve69the69Gas

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    Sounds like air to me.
    Is the auto air vent open?
    Only bleed rads with system off.

    Hth
     
  4. dslawton

    dslawton

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    Hi

    Thanks for reply. I have bled the rads with the system off, no difference.

    I'm not sure what or where an auto air vent is... I don't think it has one on the system. There's a vent pipe which goes out from the pump inlet feed pipe and up into the loft and up and over in a big loop into the water tank. But nothing that looks like a vent.

    Cheers,
     
  5. Steve69the69Gas

    Steve69the69Gas

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    They look like bike dust caps near to the pump if its got one?
     
  6. dslawton

    dslawton

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    I had a look at a photo of one to be sure... nope, I don't think it has one
     
  7. diverdee

    diverdee

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    do you have any old rads with pipes feeding top on one side and bottom on the other
     
  8. dslawton

    dslawton

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    Hi there

    No, all rads are the usual in and out of bottom on opposite sides.

    Thanks,
     
  9. ddraig

    ddraig

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    Check around pump and motorised valves for manual air vents, should be at the very top of the highest pipes.
     
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  11. dslawton

    dslawton

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    Hi there

    I've had another look, but there's definitely not an auto or manual air vent on the pipework.

    Any other ideas guys? Is it reasonable to assume that my 3 noise issues are all related? Someone at work just mentioned "pumping over" and "see sawing" to me - I checked the FAQ on these - but do you think this is something I should do the tests for in header tank, based on the symptoms I have?

    Thanks again,
     
  12. Lower

    Lower

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    Sounds like air trapped in the pump.

    Is there a bleed screw on the pump itself? There usually is in the centre of the pump.
     
  13. dslawton

    dslawton

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    Hi.

    Yes, it's a brand new pump, there is a silver screw in the middle. With heating switched off, I've tried undoing this and some water dripped out but I didn't hear any air be emitted. Should I be doing anything else other than just undoing the screw?

    Thanks,
     
  14. ddraig

    ddraig

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    Is there any way you can post a pic of the pump and surrounding valve assembly??
     
  15. dslawton

    dslawton

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    Hi guys

    As requested, I've attached some images below of the setup in the airing cupboard. Ignore all the brown plastic piping, that's just the shower pump plumbing.


    You can't see this cos the airing cupboard shelves etc are in way, but the pipe leading into top of pump boiler goes up, left, and then eventually down into the boiler which is downstairs. The smaller vent pipe comes off this pipe in a 'T' just above the white junction box and disappears up into the loft. I can't see where the cold feed joins the piping (I'd need to go into loft for that) but it's definitely not in the airing cupboard. The other white box is the wireless thermostat sender.


    Above shows further down the piping towards the base of cylinder. In between a couple of the black wires you can just see a silver in-line isoltating value (flat head screwdriver type) which is apparently a bypass (although 3 rads, 2 in bathrooms and 1 where roomstat is sited don't have TRV's anyway). The large pipe on far right, leading from the right most valve, leads under the floorboards to the radiator feeds, which in turn leads to the pipe which heads downstairs and from which I can hear the bulk of trickling per my issue (2) in original posting.

    Let me know what you think or if you need anything else...help much appreciated!

    Thanks,
     
  16. ddraig

    ddraig

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    I think if the pipe T'd in to the flow (the one above the white box) leading to the pump is a smaller size then it is the cold feed, in which case it begs the question "Where is the vent"????, you need to follow the pipes into the lost and find out how and where they are arranged, then if poss draw a diagram and post.
     
  17. dslawton

    dslawton

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    Thanks for this, will do. I'll take another look tonight... every time I try and get my head around the way the piping works, I seem to get more confused! But I now it shouldn't be that difficult. While I'm up in the loft, to kill two birds with one stone, anything else I should look for or try?
    Cheers,
     
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