Heating control question

[NjonesFermoy]

Hi guys - I've had a quick search through the forum & can't find the answer to my issue, so please forgive me if its been asked before & I missed it!

I posted this question first in the plumbing section,.. but realised its actually an electrical genius I need,.. so apologies again that I'm duplicating my question here.

So here's the story - I've just installed a solid fuel stove with a back boiler in my house and its been plumbed into the existing heating system. The original circulating pump is still in place & is currently switched on 24/7 because of the stove.

I need to figure a way of switching on the circulating pump either when the oil boiler is powered up OR when the pipe stat on the stove heats up. It needs to be activated regardless of which input requires it, or even if they both do - and it needs to only switch off if there is no power from either source.

Is there any way to easily do this??! I need a OR logic switch for mains voltages basically - possibly some kind of relay?

Many thanks in advance for your help. icon_smile.gif

 

[EFLImpudence]

I think you probably should concentrate on the plumbing and central heating replies.

It is not just a case of wiring but choosing the correct equipment and safety devices - i.e. designing a heating system.

 

[NjonesFermoy]

The plumbing side of it is all sorted - its just the electrical control thats wrecking my head,..

 

[EFLImpudence]

The plumbing side of it is all sorted -

Not if it doesn't work it isn't?

 

[NjonesFermoy]

The plumbing side of it is all sorted -

Not if it doesn't work it isn't?

It does work!

The electrical side of things needs refinement (The pump is currently running 24/7) - but the stove is lit & is heating my house.

Its a simple logic circuit on a PCB - a standard OR switch,.. I just need to translate it to a 240v ac control system or find a ready made unit that has this simple function...

 

[flameport]

Changeover pipe thermostat, with the live to the pump connected to the common terminal.
Calling terminal of the thermostat connects to the switched live from the boiler.
Satisfied terminal of the thermostat is connected to permanent live.

Scenarios:
Oil boiler on, pipe cold: pump is on, connected to the switched live from boiler.
Oil boiler on, pipe hot: pump is on, connected to the permanent live
Oil boiler off, pipe cold: pump off, as switched live via thermostat is also off
Oil boiler off, pipe hot: pump on, connected to the permanent live

This also provides pump overrun, as regardless of heat source, the pump will operate until the pipe cools below the set temperature.

Untitled

• flameport
• 21 Jan 2014
• 1

Diagram shows lives only - obviously pump also requires neutral and earth connections.

 

[NjonesFermoy]

@flameport
THANK YOU!!!

I've been wrecking my head for days trying to think of a solution & was messing around with all sorts of overly complicated ideas. This is such a simple and elegant solution and it had totally passed me by!!

 

[muggles]

The plumbing side of it is all sorted - its just the electrical control thats wrecking my head,..

The plumbing side is, from your description, really quite dangerous and shouldn't be used. See my reply to your question in the plumbing forum for more info....