PoP wrote:

Can anyone point me towards an Internet resource which gives
information about boiler size to square footage of property for a
domestic CH system? Or alternatively comment on the following?

I visited a property today to investigate the CH system not giving out
enough heat when it gets really cold. One of the things I found
immediately was that the radiators weren't balanced properly (the
return valves were full open on all that I checked), so that's one job
I've got to do.

However, the CH boiler looks like it's well underspecced for the size
of property. It's a Potterton Profile - I didn't think to get the
model number but it just looked too puny to deliver the heat required
for what is a large property - the property has been extended with an
extra floor. Physically it looked like it was the Potterton Profile
40L jobbie:

http://inspiredheating.co.uk/acatalo...FAN_FLUE_.html

If so then it's a 40,000 BTU unit.

What I'd really like to get information on is what size boiler needs
to be installed for a given square footage, if such info is available
anywhere.

Clues anyone?


It depends ENTIRELY on the standard of insulation.
My plumber (the one who thought pressure came not from teh header tank,
but teh hot water tank) almost refused to install my boiler as he
considered it only big enougjh for a three bed semi. I have (estate
agent spik) a 6 bed cottage.

Its been fine. The house is built to current regs insulation wise.

The actual calcs to size a boiler consist in doing an elemenatl loss
calculation of teh whoole outside of the house, adding in ventilation
losses, gains from south facing windows and walls, working out the heat
you want it and the worst temp the outdie will get to, and coming up
with the number of kilowatts (or BTU/H) needed to heat it.

If its any help, fully insulated house, about 400 sq meter total floor
area, and I am using a 65kBTU/H boiler.

Poorly insulated house - treble that at least.



PoP