Could anyone help me with a query on boiler sizes please. I am pricing various boilers up and have done a boiler size calculation on the SEDBUK website which throws out a boiler size of 12.7KW. When looking at specifications of various boilers they DHW input and output and CH input and output. Which one of these do I base my house size calculations on or would either of these combis be adequate. Glowworm30cxi / Vaillant 828 Ecomax. Any guidance appreciated.
Correct Boiler Size.
- Thread starter steve.c
- Start date
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DHW demand
yes they will all do it
yes they will all do it
so get yours changed then 
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to old to be let loose in the smoke babe
chrisr and agile would mug me
chrisr and agile would mug me
your boilers will modulate for the CH output and in most cases are more than capable of meeting CH demand due to the amount of kw they need to heat the DHW, in your case a 30kw will provide more than twice the amount of heat that you actually need for your central heating but this is only beacause the boiler needs 30kw for a decent hot water flow rate.
If you went for a heat only boiler then you would get away with say a 16kw boiler (12kw CH + 2kw DHW cylinder + 10%).
If you went for a heat only boiler then you would get away with say a 16kw boiler (12kw CH + 2kw DHW cylinder + 10%).
Thanks for the helpful replies. Gives me a good idea of the power I should be looking for.
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