immersion heater thermostat - sizes?

[joko]

my thermostat has packed up, but i have a spare one here already -

but it is only 11" - the one currently in my boiler is 18" - can i use the 11" one to replace it?

does it matter what length it is?

thanks

[shooty]

11 inch rods are used in pairs (1 top and 1 bottom of tank)
18 inch rods run from top to bottom (so to speak)
11 inch rod will work (not cost effective and will take a long time to heat a full tank.
I suggest you raplace it like for like.

[joko]

ah i see, ok will do, thanks

[shooty]

No worries.
Ps. Have you changed one before ?

[joko]

yes, i fitted the one i have years ago.

[joko]

im only changing the thermostat, not the element too.

[shooty]

defo need the correct stat to suit, as it wouldn't sence the tip of the rod.
I only asked so you didn't flood yourself out. there is more to changing the rod than just turning the water off. no worries : )

[joko]

nice one, thanks, ill be careful and any problems and i'll be back on here asking! :o)

[shooty]

I read the original post wrong. thought you was swapping all of it. : )

[percypineapple]

just to add abit to this, I drained my tank ( so i thought) by opening all the taps , flushing the loo etc, after turning off the incoming supply, I left it a while, tapped the tank, it sounded empty, I rocked it, it easily moved, it was nearly empty, i then tried to removed theimmersion heater with a cheapo tool from wickes, totally useless, anyway, got a leak, tried to solder it, but the tank had filled back up. WHY????? It emptied at first, and the taps were still open etc, so how did it fill??

[Dodger666]

The hot water leaves the hot water tank from the top. Opening the taps wouldn't empty it. The hot water tank also fills via the cold water tank in the loft. If you didn't tie up the ball cock the tank would have kept filling until the cold water tank was empty. Flushing the loo wouldn't affect the hot water tank.

That's assuming you have that sort of an installation.

[joko]

cant help percy, sorry, mine has thermo at the top so dont need to drain it.