Boiler question

Discussion in 'OT (OFF Topic) Forums' started by Tan, Jan 20, 2018.

  1. Tan

    Tan Hardcore MB Enthusiast

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    Hi

    We have a Vailant Boiler and it started to make a loud knocking noise, a couple of weeks ago we had a knocking noise from near the water cylinder and the water tank.

    British Gas came out first time and said monitor it for a couple of weeks, yesterday evening they came out again and said that the boiler was set to 35Kw which they said was too high, so they turned it down to 24Kw.

    We have 12 rads plus one large room with underfloor heating, but the house now feels a little cold.

    Does this sound right? Also what should the hot water and the radiator settings on the boiler be?

    We have the Evohome system and so each room has its own temperature setting.

    Thanks

    Tan
     
  2. Dryce

    Dryce MB Club Veteran

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    If it's a modern house then turnig it down to 24kW shouldn't be an issue. It may mean the house doesn't warm as quickly - but a modern boiler would normally modulate its output down to a lot lower than 24kW once the set temperature had been reached.

    Your hot water will get replenished more slowly at 24kW if there has been a lot taken.

    We had knocking on our previous boiler (Worcester - before they became Worcester Bosch). It took multiple visits to sort. The initial diagnosis was air locks, then the next was a replacement pump, and finally it was cured when the expansion vessel was replaced. The membrane in the expansion vessel had leaked so it was no longer doing its job and the knocking was the repetitions of pressure building and the relief valve releasing it when the burner was working hard.
     
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  3. Satch

    Satch Hardcore MB Enthusiast

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  4. ioweddie

    ioweddie Hardcore MB Enthusiast

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    Sound like the valve from heating to hot water, that's what mine was, but it is a combi with no tank
     
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  5. OP
    OP
    Tan

    Tan Hardcore MB Enthusiast

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    Thanks, the house is victorian set over 4 floors with the boiler in the basement and the pump and hot water cylinder on the first floor.

    We have two pumped showers with rainfall heads, so slow hot water replenishment is a concern. The pump is quite noisy and we are loosing pressure daily.
     
  6. wu56Shoozz

    wu56Shoozz Hardcore MB Enthusiast

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    How long has the banging been going on just noticed or over a period of time?
     
  7. clk320x

    clk320x MB Club Veteran

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    Mine made the knocking noise, engineer changed the pump and all was well..

    I'd recommend you cancel the British Gas plan, and take out one with Vailant direct, as I did. A proper Vailant engineer will come out with all the parts in his van, they know those models back to front and mine simply ran out the van got a new pump and plate heat exchanger and returned to refit and all was well within the hour...

    Mine also made a loud knocking noise and the water wasn't getting hot enough (as it used to)

    Regards,
    Abs
     
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  8. OP
    OP
    Tan

    Tan Hardcore MB Enthusiast

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    its been about a month now.
     

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