Whilst our CH is on the blink we've been using our immersion heater, a very rarely used item in our mains pressure HW tank.
The overheat stay tripped out last night and when I looked at the temperature setting on the Theeta WT7 stat, it was already screwed down to
20 degrees! I might have done this sometime in the past to deal with over-hot water when on the immersion and then forgotten about it.
Anyhoo, the stat doesn't seem to be doing it's job, but, before I replace it is it normal for a stat to be very loose in its sleeve (into the tank)? Just wondering if there ought to be some sort of thermal goo/paste etc to conduct the heat better from the tank to the stat.
Tim