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Central Heating question

Hypothetical question: If there is a gas boiler connected to finrads throughout the boat (and a calorifier) and a solid fuel stove, could the stove be replaced with one that includes a back boiler and just connect it in series (or parallel?) to the existing central heating system at the closest point?

Asked by: David Pinney  | 1.56pm, Tuesday 22 June

WW says:

Most solid fuel central heating systems aim to run by convection so that no pump is needed, whereas gas or oil fired systems usually have a pump to circulate the water.
To ensure good circulation, solid fuel systems are carefully designed so that the flow pipe rises steadily is it makes its way from the boiler to the various radiators. Also, the pipe work has a large diameter - 28mm is the norm - and it is all copper. This is because the stove has no thermostat which means that, if the stove is opened up, very hot water could pass round the system.
Gas or oil-fired systems can include low-mounted finrads because the pump ensures that the water will pass through them. The pipe work is usually 22mm or 15mm diameter and, since the temperature is controlled, plastic pipe work can be used.
If you want to connect a solid fuel boiler to a gas-fired system including finrads you could get round the circulation problem by installing a pump. However, if the system includes plastic pipe work, you run the serious risk of damaging it if the stove produces near-boiling water.

Graham Booth  | 10.23AM, Wednesday 23 June

I would also add that while it is (usually) fine to add to a gas boiler, such as an Alde comfort boiler (where the boiler can be set to vary the water temperature), other ones, particularly diesel powered, may not like it if you try to use the back boiler on the stove, at the same time as running the diesel boiler, as this will lead to overheating of the boiler- see the article in last months WW for more details on why this could be a problem!

Mark Langley  | 4.05PM, Wednesday 23 June

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