Hi, I have just fitted a woodburner (20 kw) with back boiler(12kw) on an existing system,pump was knackered so replaced,when the pump is turned on manually,when hot water circuit has reached 45 degrees, the hot water seems to be pumped too quickly through the boiler and the temperature drops away,radiators not getting very hot,is it possible to restrict the flow from the boiler to heat the water for longer
mike7
12 Apr 2010, 9:00 PM
Restricting the flow won't solve the problem, which I'd say is one - or a combination - of the following: Too many radiators Too small/cool a fire - for 20kW output you might expect to be burning around 7kg per hour of dry wood. A blockage in the heat exchanger, or a layer of soot/tar/ash on the hot side, or corrosion/sediment etc on the wet side reducing the effectiveness of the heat exchanger.
Fahrenheit
14 Apr 2010, 10:15 PM
What sort of size is your house? 3 bed semi? 2 bed terrace? 6 bed bungalow?
if you can give approx room sizes it would be even better.
winterbourne
1 May 2010, 6:51 PM
Does your pump have a variable speed setting? Try reducing the speed hence the velocity of the hot water in the pipes (increased heat loss) hence more for the radiators. Are you sure of the sizing of the boiler for your property?
heatstoreltd
20 May 2010, 5:06 PM
I'd reckon on approx 40,000Btu's to water which should suffice for about 8 average Rads, so that could be the issue. As an aside- If it was an existing system you fitted to- perhaps a combi boiler? was there a heat leak fitted and is it vented? vital safety features.
