Back Boiler on a solid fuel cooker.

[aceman3]

Hello everyone.

I've posted something similiar but here it goes again.

If one connects up 4 rads upstairs and two rads downstairs. The DHW cylinder is downstairs beside the solid fuel cooker. Going to use a pump to pump the water around the system. Going to use the two downstairs rads to dissipate any excess build up in temperature.
The only thing that is worrying me is thermal shock on the back boiler. Would this be a big problem to worry about or am i just reading to much into the whole situation.
Haven't put the rads in place yet, so any advice would be appreciated.

 

[oilman]

You need to run the boiler so the return temperature never drops below, say, 45 deg. This means you need a heat leak radiator of big enough output to keep enough heat in the system, to keep the return temp from dropping.

Make sure you get circulation with the downstairs radiators, before you go too far, and this MUST be gravity circulation.

The flow pipe will need a thermostat near the boiler so it starts the pump if the temperature gets too high, the return pipe needs a thermostat that stops the pump if it gets too low.

Do you have a thermostatically controlled damper on the boiler?
Do you have a sufficiently high flue?
Do you have difficult flue terminal siting problems?
What make of cooker is it?
What fuel are you using?

Is this what you wanted?

 

[aceman3]

Thanks oilman,

In a way you did answer my question.

*There isn't a thermostatically controlled damper on the boiler.
Back boiler was made especially for the cooker, as it's original one was missing. Boiler is in an L shape.
*It's a stanley Solid fuel - Sticks, coal & turf.
*Stanley cooker is mounted where an open fire place used to be, so no issue with flue.

Would be using the hall and sitting room radiators, Both will be 39" or 42" double's as the heat leak. These will be gravity feed. So a pipe thermostat on the return so as to control the return temp. My main concern would be when the pumps starts and pump's cold water from the upstairs rad's down and through the boiler. Would the thermo dynamics of the water cool the boiler quickly or would the fact that the downstairs portion of the system already being heated, dilute the cold feed and make it more temp'd.
I guess i'm thinking to deeply in the whole situation. But your feedback is much appreciated.

 

[oilman]

The return pipe thermostat will take care of it. When the pump starts, the return temp will drop, and switch off the pump. The water will heat up via the gravity circuit and the pump will start again until.............. so the cycle will continue until all the water is hot enough.