Immersion Heater in cylinder

[ray bush]

Might have to change an immersion heater in my hot water cylinder.Think its been in their for years .I know that i'll need the large spanner but dont want to buckle the cylinder .Can i just drain a few inches of water out of the cylindrer and have ago at it after i've put penetrating fluid on it and a bit of heat .

[Doc Spock]

Tricky one this. I have done a few but always a bit anxious.

Get special spanners from plumbers merchants, B & Q etc.

Put spanner on nut and ,wait for it, give it a quick hard tap with a lump hammer.

If you just try and turn it the copper cylinder may well distort. Much better to " shock " it off.

Do not heat it you may undo the soldiered boss.

[Doc Spock]

Have you checked the thermostat which runs down inside the heater.

Modern stats have a built in cut-out now, ( bl00dy EEC)

[ray bush]

The immersion thats installed is at least 20 years old.

[Doc Spock]

Is the element intact. Will current pass through it. Do you have a test meter.

Will the thermostat pull out of it's housing. They sometimes corrode inside and get stuck.

I suspect the heater was original fitted with a compound like boss white or even a putty type

That is why it needs to be "shocked off.

Have courage, take a deep breath and go for it. A short sharp tap with 2lb will shift it.

Anti-clockwise of course..

[ray bush]

Thanks for the answers .Would a little heat with a hot air gun ease the jold ointing compound .

[Doc Spock]

I doubt it, it will be like concrete after such a long time , especially afterr all the heat treatment it has been subjected to.

It WILL come off with a crack. Be brave. Turn water off first. (Hot)

[terence7556]

leave the water in untill you have cracked it at each immersion heater level, water will not pour out because you are only trying to turn it to get it started
also whenever i have taken them out heat has definately helped but its hard not to damage the insulation with the heat

[ray bush]

Thanks for the answer.
The heat that i would be applying is from a hot air stripper.My tank has a thermo-jacket which if need be i can remove .

[Doc Spock]

Heat won't work. The thread on heater is large and not a tight machine fit. The washer and sealant makes it watertight.

A short sharp belt is the only way.

[terence7556]

i agree with the doc that a short sharp shock is the way to start it off but when i changed the last pair i warmed the joints with a hot air gun and i felt this helped but you decide whatever method you like
the cylinder was pre foam insulated and the foam around the connection was easy to burn but for you this will not be a problem.( i have a jacket in my own house and it is v.poor for retaining warmth within the cylinder )

[tezestwing]

Hi ray just back off hols if you still need a bit of info if all the above failed you have one last chance all you need is a drill with 5mm bit pad saw with metal blade large pair of stillson (grips)drain off top part of cylinder then drill a series of holes across the inside brass part like a Y link with hack saw metal blade to as near to threads as you can then very carefully try to turn the unit anti clock with the stillsons if you grip the unit in such a way you will see the grips will/should encourage the unit to collapse away from the threads then remove all and thoroughly clean and prep for new HTH Tez