Any way to increase rad temp on woodfired Central Heating?

[Stevel]

Hello all,

I had a wood fire installed last September that also connects to my (indirect) cylinder. There is a thermo on one pipe near the fire. If it is on 40, the rad pump kicks in, but moves only warm water around. If I turn it above 40, the rad pump turns off, but the tank then fills with hot water quite quickly.

The radiators are never more than hand warm, and I cannot understand why I can have hot water fro showers/baths with ease, and yet the radiator never get to a hot enough temperature. There are only six in the house.

I have a niggling suspicion that something was not installed/was faulty during installation. Can anyone out there shed any light on this? I would be enormously grateful!

Thanks in advance,

Steve

 

[Goldspoon]

A couple of assumptions first:

- That the woodburner/backboiler is heating water which uses gravity to flow upwards and heat the cylinder (for hot water).

- When the returning water is at a certain temperature (hence thermostat on return pipe) the pump kicks in and diverts water through the rads.

Is the thermo on the return pipe (the one that heats up more slowly of the two)?

I have helped out on a few such installs and although not personally particularly knowledgeable as yet (my disclaimer!) but...

a) The fire has to to be of a certain size so that the back boiler is capable of generating enough heat for the rads. What are the KW ratings for your fire (X KW to the room and Y KW to the rads)? Have you tried fiercely burning wood for 1 to 1/1/2 hours? It can take this long to get everything up to temperature.

b) Good quality seasoned wood burns hotter.

If I have misunderstood your system please enlighten me.

 

[JohnD]

the amount of heat needed for a cylinder is much less than that needed to heat a house.

wood gives off far les heat than a boiler full of coal or smokeless fuel

it may be that your wood stove is not powerful enough to get all the rads hot.

Agree about needing to know the heat outputs

 

[Stevel]

Regarding output (taken form manuf'rs site):

The 12kw (40,000btu) boiler in the Broseley Hercules 12B Multifuel / woodburning boiler stove will give 4Kw of heat to the room, 8.5kw to water and 12kw to central heating: enough to power 9 standard size single radiators.

Boiler fittings on the back of the Broseley Hercules 12B Multi Fuel / wood-burning boiler Stove is 1 1/2"bsp. Boiler pressure tested in accordance with BS 3377 to 2.1 bar.

I checked the thermo by putting it up to 50. The thermo appears to be attached to the hotter of the two pipes. Could this be the problem?

I'm afraid I can't tell you if it is gravity fed or not. Is there a way I can find out?

Thanks for all input so far!