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How to remove an immersion heater element?

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Stan

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Help needed please.

There is a horizontal element at the bottom of a copper cylinder, which needs replacing. The electrics and draining the cylinder are no problem, but the @*gg£& just will not unscrew from the tank.

I have a box spanner and enough other tools. I have tried sharp taps with a hammer, heating the rim of the element and also the special WD40 release agent. But nothing works, not even tea breaks and/or copious foul language, which I sometimes find gets the job done. I have even considered drilling it out piece by piece.

I am mindful that doing it wrong will wrinkle the copper and mean a new tank.

Anyone got any great ideas? Thanks in advance.
 

TheUnicorn

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hunter27

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I have done loads of these over my working life as an heating engineer but you always get the occasional one that wont come out without damaging the cylinder, I found the best tool after using most of them was a flat ring spanner providing the immersion is not in a recess, when you hit it as you normally have to you are hitting in line with the nut unlike a box spanner where it is offset to the nut causing a twisting motion. You may have to remove some foam to get on the nut straight.
I also used to use a bit of heat if the cylinder was drained but not to much and have also run a hacksaw blade around the fibre washer joint to remove as much washer as possible assuming it is not the newer O ring variety.
Another thing that can help is having a fair bit of water in the cylinder until you have broken the seal, it stops the cylinder moving around but with a horizontal immersion you do take the risk that if the cylinder splits the water will flood out.
Good luck.
 

Artiglio

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As above , is it something that absolutely must be done? Some will never come out without trashing the tank. If it has to be done, make sure you start early and know that all the bits you need for replacement are available asap.
 

Fergie 307

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Had one like this year's ago. Like any screw thread a couple of taps as though you were trying to tighten it up first, then undo it often does the trick. When you put the new one in smear the thread with coppaslip or similar, and don't overtighten it.
 

Stan

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Thanks for all these ideas.

The element leaks into the electrics. Water is getting into the wiring space of the element from the tube the thermostat fits into. I think the whole element should be binned.

However, there is no isolation valve between the cold tank in the loft and the hot tank in the airing cupboard !!!! I had to drain the whole system. Before I try brute force ( and hopefully not ignorance ) on the element, I am going to fit one. This way, if I screw up the tank, then I only lose hot water until it is replaced, instead of ALL water.
 

Phil Pascoe

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Water is getting into the wiring space of the element from the tube the thermostat fits into ...

I had two fail inside a year for this. My immersion had the drain valve fitted right at the back, about an inch from the floor - all but impossible to get 30' of horizontal hose onto. I put the new one on a stand with the bleed point on the front with a pipe and an isolator so it was easy to empty, and also if I needed a bucket of hot water I could fill it straight from the immersion without pulling hot water all the way through the system then struggling to get the bucket in the sink.
My wife thought I was was working for nothing, but when the element failed six months later it saved a lot of time, mess and hassle.
 

guineafowl21

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WD40 (or whatever you use that’s SO much better than WD40 :p ) only works once the thing moves, even slightly.

This like getting a glow plug out of cylinder head - the bond is stronger than the thing being unscrewed. Firm persistence and a variety of methods is the key - keep trying everything, in moderation, and don’t give up.

Shock the threads with a punch. Heat around them. Soak with your favourite libation. Turn anticlockwise until the danger point, then go clockwise. Back and forth. Repeat, repeat, repeat. You will get it.
 

julianf

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If you just keep increasing the force, then the tank will twist.

Most of the bosses are braised on, rather than soldered, so can take some heat. Personally, i would hit the brass center of the immersion with a blow torch (after removing any wires that will burn) so as the heat is carried out to the edge (and thus keeps the actual boss to tank joint the coolest it can be)

Uneven expansion between the immersion and the outer thread will hopefully loosen the corroded bond.
 

Spectric

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You can see that @hunter27 has been doing these for a while, the fact he leaves the cylinder full until the immersion has been loosened is a givaway.

I think another potential clue is that the guy is in Sussex, is that not a really hard water area due to chalk?
 

clogs

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lost count of how many tanks that I have changed due to damage from this very problem......
for a client I give them 1/2 hr trying to undo the heater.....after that they get a new tank.....like it or lump it.....
I do inform them first of course......
in hard water areas it often means changing some pipe work as well due to hard water contamination....

My mums tank had the same problem in Stevenage....(I was working in Africa) before I left I signed up for B/Gas service and call out...
very lucky I did.....all the pipe work around the cylinder was change and down to the back boiler plus the cyl.......
hard water Yuk.....
If I moved to a H/Water area always fitted a softener as soon as I got the keys....
 

Woody2Shoes

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You can see that @hunter27 has been doing these for a while, the fact he leaves the cylinder full until the immersion has been loosened is a givaway.

I think another potential clue is that the guy is in Sussex, is that not a really hard water area due to chalk?
Not all Sussex is chalk - the weald, for example, is heavy clay - also pipes bring in water from neighbouring areas.
 

Woody2Shoes

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I used to live in a very hard water area in South London. Once the (zinc?) sacrificial anode inside the tank has eroded away, a new element would last only a few months before it needed replacing. I've never tried to replace a sacrificial anode - on fitting the third new element I damaged the tank and replaced the whole thing (I was pleasantly surprised how much it was worth as scrap!).
 

Stan

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Thanks all.

The little "darling" is now out. What did it was an excellent spanner with a good hammer. I bought for £8.99 a solid cast iron "Dickie Dyer" spanner from Toolstation. Don't let the lurid red colour put you off. We all know red ones go faster. The end of the handle is flattened at the sides for easy hammer strikes. The force of the strike is in line with the threads unlike the useless box spanner. Then repeated strikes in both directions did the trick, starting off gently and gradually increasing the force.

hunter27, you were spot on. Thanks.
 

hunter27

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Thanks all.

The little "darling" is now out. What did it was an excellent spanner with a good hammer. I bought for £8.99 a solid cast iron "Dickie Dyer" spanner from Toolstation. Don't let the lurid red colour put you off. We all know red ones go faster. The end of the handle is flattened at the sides for easy hammer strikes. The force of the strike is in line with the threads unlike the useless box spanner. Then repeated strikes in both directions did the trick, starting off gently and gradually increasing the force.

hunter27, you were spot on. Thanks.
Glad you got it sorted out, have used lots of different spanners but the flat ring spanners are best for this.
 

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