Immersion thermostat

You only need to turn the electricity off, remove the cover from the immersion heater and disconnect the cable from the thermostat. The thermostat just pulls out from the immersion heater element, it usually springs out slightly. See:

.. >"Mike P" wrote: .. >>A friends themostat on her old style immersion heater ... the .. >> themostat sits on the top type ... had to be switched off as the .. >> water got too hot. Now it has given up the ghost. .. >> Would you reccomend changing just the thermostat or the heating .. >> element as well. .. >> And ........ if just changing the themostat ... does the water inflow .. >> have to be turned off ? .. >>

.. >> Mike P .. >>

.. >> Mike P .. >

.. >You only need to turn the electricity off, remove the cover from the .. >immersion heater and disconnect the cable from the thermostat. The .. >thermostat just pulls out from the immersion heater element, it usually .. >springs out slightly. See: .. >

Thank you .... it will be done . :-)

Mike P

Bypass the thermostat and see if the water starts to get hot.

If so, only the thermostat needs replacing. It sits inside a sleeve in the tank and so can be removed and replaced without draining down.

If not, then the element has died. It may have overheated as a result of the faulty thermostat. Replacing the element needs the system draining down, as well as turning off the supply. It also needs a very large special hex spanner to undo it and screw in the replacement. Best to remove the existing element and get one the same - otherwise the replacment element could be too long (will hit the bottom of the tank) or too short (only heat a part of the tank).

Of course, if the owner finds that he never needs a full tank of hot water, fitting a shorter element may be a good idea..

Note that hot water cylinders now require a second non-self-resetting stat to cut the power if the main stat fails like yours did. This follows an incident where a stat failed exactly like yours did, boiled the water, which ejected boiling water back into the attic header tank. After a while, the header tank got near boiling too, the plastic tank sides collapsed, the the boiling water came crashing through the bedroom ceiling. The woman in bed at the time died sometime later from her burns.

If I could slightly hijack this thread a moment. I just had a problem with my thermostat. I've cured it but the fault puzzles me.

When the immersion was switched on it would emit a constant ting, ting noise. Eventually it stopped working and, after having bought a new immersion heater, I traced the fault to the switch on the wall. This I replaced but of course the metallic tinging noise restarted. If you pressed on the top of the stat it stopped. So I put the stat from the new immersion in. This now went ting ting ting pause ting ting ting pause. I eventually got round the problem by slightly bending the stat. Too little a bend and it went very quietly ting ting, too much and the stat was permanently on.

Why would the stat do this and why did the new stat do it differently?

Does the immersion heater assy sit in a dry hole? I've never taken one out but assumed it sits in water - then the OP is going to get rather wet??

Yep, it fits in a tube, sealed at the bottom.

Taa - gives me an idea to stop mine rattling ....