Adding a back boiler

[Speedy Jim]

If you haven't already, cross-post to: UK.D-I-Y

It's a clever idea, but there may be some pitfalls.

Jim

[dsnd_medic]

A couple of years ago I put oil central heating in my house. I live in single floor cottage and run all the piping up and through the loft a the ho****er tank was there and the cottage floor is made from cement However as we have a coal fire going nearly everyday in winter thought that if I fitted a wrap around back boiler into the hearth then it would save me a fortune in oil costs. I now have a good 2n hand back boiler but have been told it won't be as easy as I thought t plumb it into my existing system. I have an open system, ie no pressurised, My flow and return pipes are 22mm with 15mm pipes bein used to supply all the radiators. Some people say it will work fine i I just attach the back boiler to the flow and return others say I wil have major problems regulating and dissapating the heat.

Am I making a big mistake or is it a feasable idea......any comments o tips would be greatly appreciated

Thanks in advance

And

-- dsnd_medic

[Edwin Pawlowski]

Most heating systems work by the thermostat calling for heat, thus starting the circulator, the water moves around giving off heat. When it drops to a pre-set temperature, the boiler starts up to heat the water again.

In the case of an added heating source, the circulator will still work as needed. The oil fired boiler will do that also, but now the water coming back in is going to be hot already so the burner will not have to work as hard or at all. I see many benefits, a few potential problems.

If the back boiler heats the water and it is not circulating, it may turn to steam and increase pressure. You may want an aquastat that will start the circulator to prevent that.

The water passing through the back boiler may be hotter than the incoming water on the other side of the cottage making a little unbalance in room temperature. Probably not a big deal.

I'd pipe it so you have a choice of flowing through or not through the back boiler by opening and closing a couple of valves. This avoids heating it in mild weather when a coal fire is not going, or to remove it for service if ever needed.