over heating shower

[fred]

Immersion heater is over heating the water. Having shower is a dangerous exercise. Who do I call in. A plumber or an electrician ?

[Tufnell Park]

An electrician, it's most likely the thermostat stuck on in the immersion heater.

[DerbyBorn]

Tufnell Park wrote in news:pkus2q$2fp$ [e-mail]:

But first = have you tried turning it down? Howver, if not competent don't try.

I went to one and thought I was turning it down but I later realies I had been turning it up. Illogical control direction!

[Brian Gaff]

Yes. Have you checked the heater themostat. That is where I would start assuming its not n instant water heating shower, which I know nothing about at all! Brian

[John Rumm]

Sounds like the stat has failed - possibly the immersion itself is also on its last legs. Plumber would be better suited to the job since electrically its not complicated, but shifting a well corroded in heater can be a difficult job.

[Martin Brown]

Thermostat has probably welded shut. You should be able to manually switch the immersion heater off somewhere to avoid it boiling the tank.

A plumber would be my choice - the electrics for a hot water tank are not especially complicated and the main problem will be draining down to swap out the faulty part.

[Another John]

Just to be sure, and in no way trying to be funny, and I know that this has probably just happened and not gone on all summer, but: your shower is supplied by the immersion heater?

We have an electric (Mira Sport) shower. The cold water supply this summer has been so much warmer (probably only a degree or two on the supply side) to force us to turn the shower thermostat right down.

Again - apologies for the suggestion!

John

[tabbypurr]

it's diy time. Replacing the thermostat on the immersion is the almost certain solution. That's purely electrical.

NT

[harry]

Drivel. Changing a thermostat is a ten minute job that does not involve draining down

[DerbyBorn]

harry wrote in news: [e-mail]:

Just get the correct length one. Switch off - remove old - use as pattern for new one (3 length I think) Replace, Connect - Set (if not sealed) and turn on.

[Handsome Jack]

DerbyBorn posted

Why doesn't all the water come out of the HW tank when you remove the thermostat?

[Chris Hogg]

Because the thermostat is in a pocket, in effect a long tube closed at the inner end like a metal test-tube, and not directly in contact with the water. You have to get a thermostat the right length to fit the pocket, which is why DB said to remove the old one and use it as a pattern when buying the new.

[tabbypurr]

It sits in a pocket. Or less often is strapped to the outside of the tank. Leaving it run to overheat is not entirely safe.

NT

[newshound]

+1

[newshound]

Stats are normally very easy to remove and replace, though. I'd probably start with a sparks, they are also more likely to have electrical testing kit. A megger test might not be a bad idea if it is an old installation.

[Tim+]

But this is a DIY group. Changing a stat is very simple. A basic multimeter is quite good enough to test the functioning of one.

Tim

[John Rumm]

The question was, who should he *call* to do the job, not how difficult is it.

Its not a difficult job if all that needs changing is the stat - however a plumber is far more likely to have a selection of them in his van.

If it turns out the stat is not the only problem, and the whole immersion needs swapping, then a plumber is still going to be better suited (in most cases YMMV etc).

[newshound]

Oh yes indeed, but the OP was actually asking which tradesman to call. Perhaps, for example, they are disabled and can't get through a loft hatch.

And you do find, in older installations, flex which has hardened close to the heater.

[Tim+]

Well yes, but as DIYers we have a duty to help folk to DIY a job. ;-)

Tim

[John Angus]

But you do need to know how to use one. Mate of mine, a very competent mechanic, always gets me to do it for him when he needs to use one.