Unvented tank thermostat temperature

[SpecialK]

Hi,
What is the max temp I can safely heat an unvented cylinder to without issues? My current immersion stat stops at about 63 degrees.
I have a TMV on the outlet to mix down to 40 degrees.

Which immersion stat is best to use?

Its heated via solar so the more energy I can pump in the better. Im thinking of adding a water softener to stop limescale build up.

Thanks!

 

[oldbutnotdead]

What do the manufacturer's instructions say? Much over 80 you may get kettling (or maybe not in a pressurised cylinder, elevation of boiling point & all that). The emergency non-adjustable stat in the immersion heater (the wee button that pops out and needs resetting if the thing gets too hot) is probably around 80°

 

[SpecialK]

What do the manufacturer's instructions say? Much over 80 you may get kettling (or maybe not in a pressurised cylinder, elevation of boiling point & all that). The emergency non-adjustable stat in the immersion heater (the wee button that pops out and needs resetting if the thing gets too hot) is probably around 80°

Thanks. It looks like most immersions with cut outs stop at about 65 degrees so I guess its best to stick with that.

 

[conny]

Many years ago, (around 40, as near the mark), a friend called me late in the evening and asked me to pop round urgently as his immersion was making funny noises. It was in a high level cupboard in the rear sitting room and had louvre doors fitted. I heard the noise as soon as I stepped into the room and screamed at him to start running all his hot taps. It was an ominous bubbling/gurgling sound. As soon as the water started to flow the noise subsided and the tank began to clink and clank as it cooled down. Switched off the heater and then slowed the flow down to cool it more gently.
He had got a guy to fit a new heater and thermostat earlier that day as the old one had failed. Unfortunately, (maybe because he was a plumber rather than a spark? I don't know), he had wired it up direct across the element terminals and totally missed out the thermostat. As it was a sealed system, he had in fact created an unvented, very large kettle!