Immersion heater thermostats

[JohnD]

I understand that newer ones fail "off" whereas older ones could fail "on".

I have a relative whose thermostat appears to have failed "on" as the water gets very very hot, so I am planning to take it out and fit a new one. Are they interchangable, or does a new stat have to go in a new element?

 

[Agile]

It all depends on the make of element and stat.

Its questionable if you can fit an old style of stat to an old element. You can certainly fit it but it might not meet the regulations.

As far as I am aware the only regulations are that all stats being manufactured now must be the new type. I dont think there was any legislation requiring that the new one MUST be fitted.

Tony

 

[JohnD]

Ta

Oh well... I'll take the old one out and see.

Are there recognition points I can look for?

p.s. did you mean "a new style of stat to an old element"?

 

[AlanE]

I understand that newer ones fail "off" whereas older ones could fail "on".

This is not true. Old style stats can fail in either state as can the new ones!

The difference being that the new ones have inbuilt a 'high limit' stat so that if the adjustable one sticks in the closed position it prevents the water from boiling. People have been killed by this happening. Some high limit stats are resetable others are not.

There is a design of new style stat that will fit virtually all old immersion heaters.

 

[JohnD]

thanks

Is this omnivorous thermostat special? what do I ask for, or how do I recognise it?

Can I tell by looking at the old stat what kind will fit it, or do they all look the same?

 

[AlanE]

Some just have a large head which from looking at it will be obvious it probably will not fit in yours. The other is a lot smaller and will normally fit.

I think B & Q sell the 'omnivorous' one. Nothing special just different make & design.