Cylinder stat

[robsant]

I have gravity fed hot water and pumped radiators. I have a drayton tempus 7 programmer and i would like to add a cylinder stat to the cylinder.

Does anyone know the easiest way to do this?

Rob.

 

[Softus]

If you want to gain automated control over water temperature then you'll need to add a motorised valve, change the programmer to one that provides independent control of DHW and CH, and add a bypass circuit.

if you have a solid fuel boiler then there are further considerations.

 

[robsant]

Could i not just leave the programmer as it is and then have a completely independent circuit attached to cylinder that has a fused live going to the cylinder stat and then in turn going to the motorised valve.

Then when the cylinder gets too hot the valve will close, the water in the pipes will then get hotter as they will not be flowing, which would cause the boiler stat to turn off?

 

[Softus]

Could i not just leave the programmer as it is and then have a completely independent circuit attached to cylinder that has a fused live going to the cylinder stat and then in turn going to the motorised valve.

Well you could, but you'd still need to connect the MZV output to the boiler/pump, and you'd have no programmed control over what times of day the DHW is active, so it would cost you more in the long run.

Then when the cylinder gets too hot the valve will close, the water in the pipes will then get hotter as they will not be flowing, which would cause the boiler stat to turn off?

Only if that's how the boiler manufacturer stipulates that you install it, which is highly unlikely.

Repeatedly bouncing the boiler off its upper temperature limit will stress a whole bunch of components whose life will then be shortened. What you're proposing is a cheapskate solution that is inconvenient, technically inferior, and a false economy.

 

[robsant]

Thanks i will look into that, my programmer does do DHW and CH seperatly, so it should be less of a change.