pipe stats and delay off timers

[Roman]

Hi everybody,

I am in the process of replacing my old fired Rayburn with a solid fuel boiler stove. I will obviously need to alter the control system as there is no way to control the stove temp other than by closing dampers etc.

I have used much of the existing plumbing arrangement - gravity feed to indirect cylinder .... that was in place for the Rayburn.

I would like to fit a pipe stat onto the common return back to the boiler to start the central heating pump when the return temp gets to 45 degrees or so - but as soon as it starts it will throw cold water from the rads down the return and shut itself off.

Is there any way that I can use the pipe stat to start the pump but through a 'delay off' device which will keep the pump running for 5 minutes or so before shutting it down .... very much like the pump overrun in a combi boiler ? This would give the system a chance to get up to temperature without the pump stop / starting continually.

Is there any type of pipe stat that I can buy that would start the pump up at (say) 45 degrees and not shut it down until the temp dropped to (say) 30 degrees.

Does anybody have any experience with this ? Could you suggest where I might be able to find the bits I need to do the job ?

Thanks in anticipation.

Roman

 

[Plouasne]

I would be thinking about the pump on the return, with an injector "tee" for the gravity return from the cylinder just after the pump, the pump controlled by a room stat via a pipe stat on the gravity return, to stop it from running before the return got up to the correct temperature, to stop condensation in the boiler, this way there will be or should be gravity circulation to help dissipate the heat if the pump fails for any reason, this together with a heat dump radiator ( a radiator taken of the cylinder flow and return, without any valves on it)

 

[Roman]

I would be thinking about the pump on the return, with an injector "tee" for the gravity return from the cylinder just after the pump, the pump controlled by a room stat via a pipe stat on the gravity return, to stop it from running before the return got up to the correct temperature, to stop condensation in the boiler, this way there will be or should be gravity circulation to help dissipate the heat if the pump fails for any reason, this together with a heat dump radiator ( a radiator taken of the cylinder flow and return, without any valves on it)

Thanks for the response. This is exactly how it is set up at the moment - room stat - pump on return before the gravity feed from the cylinder joins - the return from the pump runs along the top bar of the tee with the cylinder return joining it.

My question though is it seems as if the room stat is now redundant - after all with a solid fuel boiler it can't up the heat output. I wanted to run it all from a pipe stat - in other words I light the fire - the hot water cylinder gets up to temp - and then the circulation pump kicks in to dump all the heat around the rads. If we want more heat then we put more wood/coal on the fire.
The only thing I want to stop is cold water being pumped around the system with the corrosion problems that would cause.
However - a simple pipe stat will be fine for turning the pump on - but as soon as it cools down (almost at once) when the cold water is pulled out of my rads it will turn off again.
So - I want to turn it on when the return temp gets up to 45 degrees and to stay on until the return temp drops to 30 degrees ......
OR
Have a pipe stat with a pump overrun time so that it stays on for at least 5 minutes after the pipe stat detects the temp dropping below 45 degrees.

I am sorry if I am not expressing this clearly - it seems sensible to me ..... any other ideas please ?

Thanks again

 

[pedder63]

I am currently installing a boiler stove. The best way to do this seems to be to use one of these, Esbe vtc load valves - vtc312 vtc 317 vtc 500 uk , a load valve which gradually lets hot water into your heating circuit, while simultaneously circulating hot water round your boiler. Hope this helps.

Peter

 

[kenneth11]

you could try a strap on cylinder stat,when this reaches the required temp ,it will kick on the pump to circulate to the rads,with another pipe stat on the return to shut the pump off

sorry the other pipe stat on the flow