Tips on removing old immersion heater?

[Stephen Fasham]

The immersion heater currently fitted to my hot water tank is a) a short one (so only heats half the tank - if that) b) has no working thermostat so has a tendency to boil over into the cold feeder tank unless run in v. short bursts, and c) has started to suffer from that very particular smell of electrical burning.

All of this has led me to the conclusion that replacement is in order. However I have tried removing it and the bugger is well stuck such that I am a little concerned about ripping the port out of the cylinder rather than the heater out of the port. I don't really want to change the cylinder as although its small, crap and unlagged the whole CH/HW system is due for change next year.

Does anybody have any tips/experience on how to get it out without creating too much devastation and expense?

Fash

[Grunff]

Use generous amounts of penetrating oil (e.g. PlusGas - not WD40) on it. But sometimes they just won't come out without tearing the cylinder - you just have to accept that. If the torque required to get it moving is higher than the torque required to rip the cylinder there's not much you can do.

Sharp taps on the spanner, rather than a constant force, can help.

[Christian McArdle]

Leave it in there and disconnect it. Install a new side entry immersion and boss near the bottom into a new hole.

Christian.

[BigGuyUK]

Use a Blow torch to warm the Threads, Seal. Let it cool down then put the spanner on and give it a good tap with a hammer this should shock it and get it moving. Or dig the seal out and spray with release oil do this over a day or two to give it chance to penetrate. Then try to tighten it. As this will free it off then unscrew it out. If you use release oil always give it a day or two to soak in. BigGuyUK

[Clive Summerfield]

Another tip: don't completely drain the tank before trying to remove the heater.

Cheers Clive

[Stephen Fasham]

Thanks for all the advice, I have gone for a half-way house solution.

Basically I pulled the thermostat out (which was clearly the cause of the burning smell - only about half the plastic still left unmelted), took it with me to B&Q and bought an immersion heater with the same size stat (significantly more expensive than buying from screwfix - but you can at least check for fit). I then replaced the stat keeping the rest of the new immersion heater, since I may want it when I replace the HW system properly at which point I will recover the stat.

This fixes the burning smell and the boiling over. I'm still left with the fact that the immersion only heats up the top third of the cylinder, so I have cheated by cranking the thermostat up to max for the moment, on the grounds that whilst I know the heat loss will be more I have fitted a new insulation jacket and I can heat a lot of water for the cost of prematurely replacing the cylinder since when I do it for real I'm going for a Pandora type jobby anyway.

Thanks again,

Fash