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Any UK Contractors Out There?

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Rich Davis_2
Rich Davis_2 Member Posts: 117
My daughter lives in Slough in a 1 bedroom flat, about 600 Sq Ft. She's wanting to put in a combi central heating system. She had two estimates, British Gas and Southern Gas and Elect. 1, was for 30KW and the other a 24KW boilers, which to me seems kinda more than she needs. I don't know what's available over there. I'm note sure if they done a heat loss. I designed and installed my own Mod/Con heating system a couple years ago. I would like to find out what youse think from across the pond. Thanks loads.

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  • Rich Davis_2
    Rich Davis_2 Member Posts: 117
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    Also I forgot to ask is that KW figured on input or output?
  • delta T
    delta T Member Posts: 884
    edited March 2018
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    Well a combi unit will generally end up being oversized for heating as it has to keep up with an instantaneous DHW demand. The 30 kW model (assuming input and a 92% efficiency, and a 75 F degree rise) will give you about 2.7 gpm of hot water. This is enough to run one shower with just a little left over, so you are not going to downsize much more if the boiler is to keep up with the DHW load. The 24kW model (same assumptions) will deliver about 2.2 gpm. Chances are that the heat loss on a -10 degree design day (this is most likely overkill) will be less than 5 kW. To my knowledge there is not any fuel burning appliance designed for use as a central heating plant anywhere close to that small. Have you thought about electric? Not sure what the electrical rates are out there, but perhaps a small electric boiler for the heating and then a dedicated fuel burning on demand water heater?

    Here at least most boilers are rated on input, I used that assumption for these numbers. We use British Thermal units (BTUs) almost exclusively over here, kind of funny that its kW over the water :)

    1 kW = 3,412 Btu/hr

    Hope this helps!
  • Rich Davis_2
    Rich Davis_2 Member Posts: 117
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    I forgot to say the water for her shower has it's own electric heater and calledna (electric Shower so the combi will only be heating the water for her kitchen.
  • delta T
    delta T Member Posts: 884
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    Also forgot to mention that most combi units will modulate down to satisfy the heating load, so it will not be trying to shove 30 kW into the heating side if it is not necessary, but there is a limit to that modulation, so most likely it will short cycle in the warmer months when in heating mode.
  • delta T
    delta T Member Posts: 884
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    Is there a dishwasher in the kitchen?
  • kcopp
    kcopp Member Posts: 4,441
    edited March 2018
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    I converse w/ a bunch of contractors in the UK. I have not heard many good things about British gas. They do things a lot more sophisticated over there.
    Let me put the word out.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,614
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    Could be a field trip!!
    delta T
  • kcopp
    kcopp Member Posts: 4,441
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    Here you go...

    Patrick Wheeler tel. 07723090894 Patrick@elementalheating.co.uk

    Mike Walton Property Maintenance on - Tel: 01344300248
  • kcopp
    kcopp Member Posts: 4,441
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    Anything become of this?