Link ins to Other Systems

With the continuing and soaring costs of oil and other heating fuels, we are constantly being asked about linking automatic fuel boiler systems to wood burning in order to manage running costs.

We find ourselves saying the same things over and over again. Here's a summary of the most oft repeated points to consider.

Pressurised systems.

No you can't! (Technically it can be done, but you break so many rules and principles en route it's not worth the risk or effort!)

Cost.

You cannot do this on the cheap! There are technical issues arising that need relatively expensive kit to overcome, and the services of a well trained heating engineer.

Stove v Boiler.

The biggest water heating stoves in the market will generate around 80k btu's, but they are huge! A small boiler for a kitchen or outhouse site, will offer more efficiency, higher output ranges often at a comparable cost

VAT Note, from January 2007 vat on new woodburning boiler systems is 5%

Technical

I so often see this done wrong it's scary!

You must not fully pump a solid fuel heating system.

Think about it. If you are using an oil or gas boiler and there is a power cut, not only does the central heating pump stop, but the boiler overheats and goes out.

Most systems are "Fail safe". A solid fuel system will carry on producing hot water as long as there is fuel in the fire to burn.

You must engineer a "Gravity circuit", i.e. a proportion of your heating system that doesn't rely on the pump to operate, thus allowing hot water to circulate away from the boiler and cool down.

Prevent reverse circulation.

Your boilers are connected to your heating system by wide bore pipes. Often 28mm and occasionally on larger systems by 35mm.

Put yourself in the position of the water in your system. If you have simply grabbed two big pipes to connect a new boiler to your system, are you going to choose to take the hard way down microbore pipes to radiators when there is an easy, big pipe to go down? If your oil or gas boiler is consistently allowed to heat your solid fuel boilers water jacket then the end result may be your heating bill going up, not down.

Controls.

Most of us have got very used to our techie toys, most of which (You're not going to want to hear this) are redundant! Sure you can fit a time-clock to your solid fuel system, but since you're going to have to get up in the morning to put a log on anyway, what's the point?!

A room thermostat, similarly could be calling for heat when you are not at home to feed the fire. Manufacturers of solid fuel boilers are paranoid about controls, with good reason.

A badly installed control system will not only drive you potty, but can even destroy your boiler, if not set up to prevent condensation occurring.

Alternatives.

Do you really need to connect to the central heating system to reduce your oil / gas costs? A small stove, in the average living room will be generating so much heat that the radiator in that room will be off. (Thermostatic radiator valves are a must!)

A bigger stove, with doors left open in to other rooms may well heat a substantial proportion of your property, again radiators dropping out of the system as the house heats up. Result, comfort level going up. Fuel bills going down!

Please note, I am NOT a heating engineer or plumber, and make no claims to be, but the above points are not rocket science, but simple logic.

DO consult with a trained (Preferably HETAS) engineer. He or she has invested a lot of time, effort, and often cash in learning how to do these things correctly and safely.

And a simple but often neglected point. How do you find such an engineer? ASK! Ask your friends, relatives, yellow pages, HETAS, anybody! Then ask the engineer for references. If he / she has done this before, successfully, then they have a happy customer somewhere who will be glad to talk about it. ASK!

VERY useful links

The Solid Fuel Association

www.solidfuel.co.uk The website of the solid fuel association. Peruse the "Literature" menu and download, or order (FOC) the "Guide to link up". A superb document, and almost the bible for the project

HETAS

www.hetas.co.uk The governing body for the solid fuel industry in England but operates a UK-wide registration scheme for solid fuel engineers.