Flexible HW/CH Controller

[DanInit]

Does anyone know of a controller that will handle the following crazy setup?

Currently, boiler with two circuits, one rads the other indirect hot water. Both circuits independently pumped with no 2-port valves, no cylinder stat, no room stat, no controller. Was old gravity HW, with pump added. Both pumps and boiler on timer plugs.

Works fine as is, but want to add room stat and cylinder stat without having to upgrade entire system. Anyone know if a controller exists that will handle this?

 

[ShaunCorbs]

any two channel programmer should be fine (the pumps act like a 2 port valve)

how is the hot water cylinder temp controlled?

 

[DanInit]

It isn't at the moment. I just make sure that the HW pump and boiler are on only long enough to either heat from cold or top up. This is why I'd like to add a controller.

With a two channel controller, would it be a case of wiring in the pumps into where the two port valves should be?

 

[snowhead]

how is the hot water cylinder temp controlled?

Off the boiler stat I'd guess, same as gravity would have been.

 

[DanInit]

I meant to say....

...why I want to add a room stat, cylinder stat and controller....

 

[ShaunCorbs]

Off the boiler stat I'd guess, same as gravity would have been.

yea just left at 60 and run it for an hour on hot water

 

[ShaunCorbs]

It isn't at the moment. I just make sure that the HW pump and boiler are on only long enough to either heat from cold or top up. This is why I'd like to add a controller.

With a two channel controller, would it be a case of wiring in the pumps into where the two port valves should be?

yes straight out of prog to pumps and live to the boiler

note any wiring to the boiler needs to be done by a gas safe engy

 

[DanInit]

Absolutely, thanks very much for the help, so much more simplistic than I thought!

 

[ShaunCorbs]

Absolutely, thanks very much for the help, so much more simplistic than I thought!

i would recommend fitting a cylinder stat and wiring that in to turn the pump off when the cylinders upto temp tho

 

[DanInit]

Yep definitely, a room stat, cylinder stat and controller..heaven

 

[ShaunCorbs]

Yep definitely, a room stat, cylinder stat and controller..heaven

sounds like your sorted any problems / success keep us updated either way

 

[DanInit]

I've been thinking about the wiring on this. Looking at an s-plan wiring schematic, I'm not sure how to get around the absence of the switches on the valves which isolate each other when using a common switched live for the boiler.

I can see how to wire up the two pumps with two stats, but when the boiler becomes live it seems to me it will complete the circuit for both pumps as well. How can I make sure each pump is isolated from the other channel without some other switch?

 

[ShaunCorbs]

Need to use two relays

 

[DanInit]

So simply replace the switches with relays in an s-plan schematic?

 

[ShaunCorbs]

So simply replace the switches with relays in an s-plan schematic?

Unless you want to install port valves that's the only other way to stop one side backfeeding the other pumps

 

[DanInit]

Ok thanks. Any suggestion for a suitable relay?

 

[ShaunCorbs]

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