How to tell what size immersion thermostat I have?

[Bill]

Before I've taken it all apart???

It's a normal sized, vented hot water tank and the thermostat has started tripping out.



It's tight under a shelf so whipping it out for a quick look is a PITA.


ETA we're in a hard water area so they don't last long anyway, makes sense to replace the lot doesn't it?

Edited by Bill on Tuesday 28th June 09:56

[Bill]

Thanks, it's a fairly new steel tank and the old one split when the last immersion failed. It's probably 4 years old.