On 14 Jan 2007 13:08:36 -0800 someone who may be "Bodgit"
wrote this:-

Currently I have 2 boilers: an oil boiler for CH and a small LPG
multipoint for DHW. I would like to ditch the multipoint and add a
heatbank to the oil boiler system to get mains pressure hot water. [snip]

What factors affect what the output power can be set to? Is it possible
to increase the output power or will that damage the boiler?

What is the result of your heat loss calculation for the house? How
does this compare to the boiler power?

How large a heatbank do you wish to have? How quickly do you want to
heat it? How will it be controlled? How will the heating be
connected to it? What sort of hot water usage do you have?

Having cogitated on that the answer to your questions may be that
the current boiler settings will work fine. Provided the boiler is
capable of putting heat in faster than the heating and hot water is
taking heat out, the bank will remain charged. Even if, for
relatively short periods, the boiler is not charging the bank fast
enough this may not be a problem as there will then be time for it
to "catch up".

None of us will do the donkey work of calculations for you (well I
assume nobody is that generous), but if it looked in the right
ballpark I would be inclined to give it a try and see. One strategy
would be to couple up the heating and measure how it behaves as
stage 1. If it works move part or all of the hot water across and
see how it behaves as stage 2. Fiddle if necessary. The multipoint
can be retained in reserve, with suitable valving to change between
the two. Stage 3 is to remove the multipoint heater after everything
is working as you want.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54