Is my boiler big enough?

Discussion in 'Plumbers' Talk' started by weeleyboy, Nov 26, 2014.

  1. weeleyboy

    weeleyboy New Member

    We live in a 2 bedroom chalet bungalow and find that my radiators never get really hot even when firing up from cold and we struggle to keep the house warm when it's really cold. We have the following radiators installed:-
    2 off 500 x 600mm double
    1 off 700 x 600mm double
    1 off 800 x 600mm double
    2 off 900 x 500mm double
    1 off 900 x 500mm single
    1 off 1000 x 500mm double
    1 off 1200 x 500mm double
    This is served by an old Halstead 60,000 btu boiler and the hot water is topped up by an immersion heater. Should this size boiler be able to cope with this number of radiators or are we underpowered? I'm reluctant to part with the old boiler while it's still working but realise I may need to install a larger one.
    Any advice much appreciated.
     
  2. Walt Systems

    Walt Systems Member

    The boiler is well big enough. Get the boiler and system checked out.
     
    FatHands likes this.
  3. Dave does Gas

    Dave does Gas Screwfix Select

    All you need for that including the water is an 18 Kw boiler so yours is more than capable. When you run your system feel the radiators if they are warm at the top and cold at the bottom that would indicate that you have a dirty system that would benifit from a power flush. Also have the radiators been sized correctly for the heat loss of a room or just chucked in to look aesthetically pleasing? Is your system Microbore? do some radiators get hotter than others? If so the system will need balancing.
     
  4. weeleyboy

    weeleyboy New Member

    Thanks guys, at least the boiler seems the right one. The pump is a Wilo Gold RS50 with three flow settings, 65 51 and 35 it's currently on the middle setting - is this correct? The boiler is controlled by a portable room stat which starts and stops the boiler but the boiler never seems to run for long before switching off again. As I've said, none of the rads ever get hot enough to feel uncomfortable when touched.
     
  5. sam spade

    sam spade Active Member

    You have approx 12kW of rads and a boiler giving out approx 17kw. So, if anything, the boiler is oversized.

    Use http://www.idhee.org.uk/calculator.html to check what size boiler you should have. If it's much less than the existing boiler, you may have noticed your boiler continually turning on and off (cycling) this is because it is producing heat faster than the rads can pump it out. The boiler will need down-rating, if that's possible with your particular model. Which is??
     
  6. weeleyboy

    weeleyboy New Member

    Thanks Sam, the boiler is a Halstead Best DB60 and it says min water flow needed is 22.9L/min. There is a temperature dial with a scale of 1 to 5 which is currently set at no 5
     
  7. sam spade

    sam spade Active Member

    I'm unsure if the DB60 can be range rated. All other version can, but the Installation Manual is vague about the DB60. I can't see any reason why not as the same gas valve is used on all versions. Hopefully one of the GSRs can confirm.
     

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