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    • andre_xs
    • By andre_xs 13th Jan 18, 3:11 PM
    • 97Posts
    • 21Thanks
    Boiler: no continuous warm water
    • #1
    • 13th Jan 18, 3:11 PM
    Boiler: no continuous warm water 13th Jan 18 at 3:11 PM
    our boiler is behaving a bit "funny":
    When we take warm water for a longer time (e.g. having a shower), then the water gets nicely hot in the beginning, but after a few minutes it starts to get colder and colder, then warm again, then cold again, and so forth. When I look at the boiler I can see that the burner/flame is not continuously on, it goes on for a minute or so, then off for a minute, and so forth. This is not always the case, sometimes it runs continuously. It hapens when we take water from any tap, and I tried different heat settings on the boiler.

    When the boiler works for the central heating, then the burner/flame runs continuously without any problems.

    It is a quite old (10-12 years) Isar HE24 boiler.

    Does anyone know what may cause this type of problem (and roughly how much a repair is and whether it can be done by oneself)?

    A related question: If I asked a boiler repair person to give me a quote what the repair costs, does that typically already cost something (i.e. coming out to give a quote) or is that free?

    Best wishes,
Page 1
    • Alex1983
    • By Alex1983 13th Jan 18, 3:26 PM
    • 823 Posts
    • 487 Thanks
    • #2
    • 13th Jan 18, 3:26 PM
    • #2
    • 13th Jan 18, 3:26 PM
    Sounds like a restriction in your plate heat exchanger
    • blackshirtuk
    • By blackshirtuk 13th Jan 18, 4:46 PM
    • 518 Posts
    • 292 Thanks
    • #3
    • 13th Jan 18, 4:46 PM
    • #3
    • 13th Jan 18, 4:46 PM
    As above,
    Your boiler is heating the water but due to a restriction, possibly scale the water heats too quickly which causes the overheat sensor to cut off the gas, until the water is cool enough for the sensor to allow heating again.

    You will need either the heat exchanger de-scaled or replaced.

    As a short term "fix" turn the water temperature down, the allows the water to flow for longer before the sensor is triggered because the water isn't being heated as much
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