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Discuss Logic Plus 35kw - Regular low pressure warnings in the Central Heating Forum area at

  1. Rob Clark

    Rob Clark New Member

    Hi all, any help appreciated.

    Had a Logic Plus 35kw combi installed in early 2016. All working great until recently.

    Late Nov last year, we got the following error;
    'Low Water Pressure - 1 fill system to 1.0 bar - 2 bleed rads - 3 contact installer'

    Good news is filling the system worked and boiler came back on.

    December, happened again. Filling system worked again. Now happened a further two times. Filling system works each time.

    Any ideas what might be causing it and how I might prevent it from happening? It's a bit of a pain as the boiler is in the loft space.

    Many thanks,
    • Informative Informative x 1
  2. Craig Watson

    Craig Watson Plumber GSR Top Contributor!!

    Sound like you have a steady loss of pressure. Have you noticed any water dripping from the prv outside at all?
    • Like Like x 1
  3. Rob Clark

    Rob Clark New Member

    Thanks for coming back Craig. That's the weird thing - first thing that occurred to me was leak. However I've checked the boiler, and no signs of leaking, and I've also check as much of the rest of our central heating system as is visible and can't see anything.. Maybe under the floor I suppose...
  4. king of pipes

    king of pipes Trusted Plumber GSR

    Must have a leak somewhere bud ? the boiler has a 7 year warranty you could get Ideal out to check the boiler over but beware if it turns out to be leakage from somewhere else they will charge you . Kop
    • Like Like x 1
  5. Craig Watson

    Craig Watson Plumber GSR Top Contributor!!

    It could be coming from anywhere. If your topping up every couple of weeks then it's likely not a big leak so could take some time before any signs of a leak appear in your house. I'd call an enginner to check your boiler and system over.
    • Like Like x 1
  6. scott_d

    scott_d Plumber GSR Top Contributor!!

    Call the installer. Expect to pay if it’s nit a boiler fault.
    • Like Like x 1
  7. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    Erm , this could be a problem within the boiler , dont assume its the system , you need a gas safe guy to look
    • Like Like x 3
    • Agree Agree x 1
  8. bogrodder

    bogrodder Plumber GSR

    I do hope warranty has been registered, you may need it
    • Like Like x 2
    • Funny Funny x 1
  9. Harvest Fields

    Harvest Fields S. Mod Trusted Plumber GSR Top Contributor!!

    Get an engineer out mate. If no visible leaks he will know where to look.
    • Like Like x 1
    • Winner Winner x 1
  10. Rob Clark

    Rob Clark New Member

    Thank you to everybody who has responded, it is much appreciated.

    I've had a good look over the boiler, the piping from this and the visible piping to the heating systems and I still can't see any leak. So as suggested on here, I'll get a engineer out.

    Yes, boiler is under warranty and warranty is registered.

    Just a side point. Called Ideal - they said there is no risk of charges against me even if it is a leak. They apparently just investigate the boiler and if they can rule it out as the cause, they will simply advise that I call a plumber to investigate for a leak as a next step. They don't charge for call outs etc. Actually very impressed with the service so far.
    • Like Like x 3
    Last edited: Jan 11, 2019
  11. John.g

    John.g Active Member

    If you happen to be there at the time that Ideal come to check the system you might ask them if the expansion vessel pre charge and cold fill pressure are the same, 1.0 bar in your case, this seems to be the "standard" procedure because the integrated expansion vessels are so compact that there is little/no allowance for a small cold fill reserve in the expansion vessel. This is achieved by having a differential of 0.3/0.5 bar between the the pre charge pressure and the cold fill pressure (pre charge always < cold fill pressure). For example if the boiler has a 8 litre expansion vessel fitted then there will be a 2 litre cold fill reserve with a pre charge of 0.5 bar and a fill pressure of 1 bar. Assuming system contents of 100 litres and a 2.5% expansion then the final pressure would be 2.4 bar.
    I know that 2 litre reserve wold be quickly used up if you have a leak but IMO by having no reserve whatsoever means that there is far more frequent topping up even in a "100%" tight system as water is incompressible.
    • Like Like x 1
    • Informative Informative x 1
  12. Rob Clark

    Rob Clark New Member

    I thought I would return and let you know the resolution.

    The Ideal engineer found that the heat exchanger in the boiler was leaking. He replaced the unit which took about an hour and a half.

    Fingers crossed that’s the end of that.

    Thanks again everybody.
    • Informative Informative x 1
  13. Craig Watson

    Craig Watson Plumber GSR Top Contributor!!

    That's not good for a 3 year old boiler, lucky you had the warranty.
    • Like Like x 1
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