New home heating issue

Discussion in 'Plumbers' Talk' started by JJ88, Feb 9, 2021.

  1. JJ88

    JJ88 New Member


    I have just moved into a new home and have found a problem with central heating system.
    The house has been extended since the boiler was last fitted but the radiators in the extension get lukewarm at best, one gets no heat at all and even the lukewarm ones take a very long time to heat up.
    The boiler is getting towards the end of its life ( it was fitted in 06 )
    Was thinking that the issue may be the boiler is not powerful enough to heat the house?
    I have turned all radiators apart from the extension ones and they do get warmer but not as hot as they should.

    do you think that a new more powerful boiler should fix this or could there be something else going on?

    cheers for any help!
  2. Dot99

    Dot99 Member

    System(rads) may need to be balanced.
  3. andy48

    andy48 Screwfix Select

    1. As Dot99 says, balancing may be the issue. Try turning off all but the problem radiators at their TRVs or wheel head valves. Don't touch the lock shield valves. If the problem radiators then get hot, very likely to be balancing.
    2. If the problems are all in the extended part of the property, it is possible the builders or their plumbers have just tee'd off the 15 mm supply to an existing radiator, rather than going back to the 22 mm spine (if there is one). Very hard to determine without getting under floors. If this is the case, will need re-piping, at least in part.
    3. Very unlikely to be the boiler. Count the number of radiators, multiply by 1.5 and add 2. This gives a very rough approximation of the heat requirements of the property in kW. If this is a good bit less than the kW capacity of the boiler, then the boiler is not likely to be the culprit. If the number is greater than or equal to the boiler capacity, you may need a bigger boiler. A lot depends on the level of insulation present in, loft, walls, windows.
  4. JJ88

    JJ88 New Member

  5. BillyBobToo

    BillyBobToo Active Member

    Why do you think the boiler is near the end of its life? 15 years isn't that old.
  6. dcox

    dcox Screwfix Select

    Sadly I’d agree that 15 years is about where a lot of modern boilers become uneconomic to repair.

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