Correct thermostat for Steel hot water cylinder

[Bifta]

I took this as well if it helps to tell whereabouts it is. It’s approx one third up the cylinder.

 

[Elkato531]

there are long periods when the pump is still circulating

But is the boiler firing? Pump over run is controlled by the boiler not the cylinder stat.

 

[Elkato531]

because there is still latent heat within the casing

No that isn't correct. The walls of the cylinder are so thin that the difference between the thermal conductivity of copper and steel will be negligible.

 

[Bifta]

Thanks for the replies Elkato.

Regarding the boiler firing, I will have to sit with it one time during a cylinder heating phase and make a log of when and how long it fires for to be sure.

That’s useful to know regarding how thin the walls of the cylinder may be. If that’s the case then it shouldn’t matter what type of stat it is, just that it’s positioned correctly. This would also explain why when I google search “thermostat for steel hot water cylinder”, I just get the usual type of stat and nothing specific for steel.