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New boiler - poor flow - total noob question

Discussion in 'Plumbing and Central Heating' started by m112, 23 May 2019.

  1. m112

    m112

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    Hello,

    I've had an old Worcester replaced with one of the latest Intergas + Opentherm.

    New boiler works fine with DHW however the problem is with a CH.

    It appears that boiler has very slow/weak pump - when I set a temperature on the thermostat to 30C boiler fires up for minute and then stops, after 2-3 minutes fires up again. The flow pipe from the boiler is very hot however the raidator are only slightly warm - despite having the TRV open to max.

    I've never had a problem with CH before and radiators were heating quickly with an old boiler.

    The boiler installer put some cleaning fernox cleaner into the system - somehow manually flashed it for a couple of minutes - but never open radiators when doing so - then they removed the dirty water, topped up Fernox inhibitor and filled out with the fresh water.

    And now the question.

    I started to think that Intergas boiler has either a very weak pump or the installer blocked pipes "while cleaning" which now causes a problem with the flow. This affects all radiators.

    What do you think?
     
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  3. easyflow

    easyflow

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    Slow weak ? more like a strong powerful pump, look towards installation and the condition of your systems carcass and radiators.
     
  4. Elkato531

    Elkato531

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    Almost certainly no problem with the boiler or pump. Get the installer back to sort it.
     
  5. muggles

    muggles

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    The Intergas pump is far from weak. Its power can be set in the installer menu, and usually needs turning down rather than up. It may be stuck however - every single Intergas boiler is fully tested in the factory and the residual water can cause a small amount of corrosion in the pump body, which in turn makes the pump a bit stiff. Turning it up to maximum temporarily usually cures it, but sometimes the boiler needs to be drained and the pump head removed to spin it and free it. Thereafter, it will give many years of good service.

    I have to day that the suggestion your system may not have been cleaned properly is rather worrying though. No manufacturer will honour the warranty on hydraulic components where the cause of premature failure is a dirty system...
     
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  6. I would check your return valve first, I’ve been to many of these where they have simply been left shut, so when calling for heat, the boiler will fire up,flow pipe gets red hot, but no circulation is occurring.

    If your unsure if it’s open or closed, post a photo.
     
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  7. ServiceNumpty

    ServiceNumpty

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    Doesn't the boiler show a no flow fault code, or overheat code.
     
  8. Crap quality then.
     
  9. Razor900

    Razor900

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    Don't open the case or let anyone play with the pump. I can guarantee that no casual installer is familiar with the internals of the new Intergas yet.

    Just call Intergas under the warranty ;)
     
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  11. muggles

    muggles

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    Far from it - Intergas are one of the few companies who still use metal pump housings rather than cheap nasty plastic ones
     
  12. m112

    m112

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    I think i managed to fix the issue, it was caused by an air inside the boiler. There is an air blead valve on the top which i used
     
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  13. It usually is something simples! :D
     
  14. bernardgreen

    bernardgreen

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    View the testing HERE

    Something is less than perfect.

    Can residual water left in the pump after testing really cause enough corrosion to prevent the pump operating ?

    If that corrosion can happen then the test rig should "blow dry" the CH circuit before passing the boiler on to the next stage.
     
  15. And first thing you need to do to new one is repair it!....Crap quality.
     
  16. Quite.
     
  17. ianmcd

    ianmcd

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    do you spin the drums of every washing machine you fit Dumberplumber? you are not exactly qualified to comment on one of the best made boilers on the market at present
     
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