Removing stuck immersion heater

[Richard Skeen]

The element has failed in one of the two immersion heaters on my hot water cylinder. The problem is, I'm having real difficulty removing it so I can fit a replacement.

I bought this spanner, but can't unscrew the immersion by hand:

far I've tried: standing on one end of the tommy bar, levering up the other end against the floor with a car jack, and hitting it with a 4lb club hammer, although admittedly not all at the same time. All I've achieved is bending the cylinder at the immersion heater boss, even though I kept it full of water for strength.

Does anyone have any tips? The cylinder is probably about 12 years old and this is a hard water area, so I imagine it's scaled up on the inside. Any point in trying to soak penetrating oil into it overnight? As it's a combination (fortic) type cylinder, it wouldn't be cheap to replace.

Thanks for any suggestions, Rich.

[Andy Cap]

Plusgas is better but I can't imagine it will have any effect on the internal scale.

Andy

[Martin Pentreath]

hand:

> So far I've tried: standing on one end of the tommy bar, levering up the

Hi Rich,

As you're aware, you do have to be careful not to apply so much force that you distort the cylinder. The last time I had to do this I did it by greatly increasing the leverage on the spanner using a scaffold pole over its handle and applying gentle and steady force. It took two people, one to hold one end of the pole over the spanner handle and the other at the other end applying force.

Cheers!

Martin

[John]

Crickey! You could tear the copper. Keep going with the Plus Gas. Good Luck

[David Hansen]

On Fri, 04 Apr 2008 12:20:43 +0100 someone who may be Richard Skeen wrote this:-

What you seek may not be possible. I would locate a suitable rapidly deliverable replacement before trying too hard, in case the cylinder dies during the operation.

Whether you manage to get the old one out or not it would probably be a good idea to practice some preventative maintenance in future, by slackening off the heater every year or so. Obviously lower the water level first.

[Appin]

The message from Richard Skeen contains these words:

So far I've tried: standing on one end of the tommy bar, levering up the

You haven't given the model number or the location of the immersion heater boss.

However, it frequently happens in hard water areas that the immersion heater gets set in so solid there's no way you're going to get it out.

Usual answer is to fit a mechanical flange in a fresh hole cut for the purpose. Dependss how congested the tank is -- you may be able to leave the existing immersion heater untouched. You may be able to bend it out of the road.

[Cicero]

================================== Borrow or hire a large pair of stilsons. Grip the flange with the stilsons and apply *gentle* anti-clockwise pressure and whilst maintaining the pressure tap the end of the stilsons with a lump hammer - light taps only.

If you can apply heat whilst doing the above it might help.

Cic.

[John Stumbles]

Just keep tapping away at the end of the spanner with a hammer until it frees up enough to turn by hand. Don't wack it and ferf*cksake don't lever on it ( too late).

[Dave Liquorice]

Have you also tried tightening it? Couple of knocks one way, couple the other. A decent squirt of plusgas and left overnight may help.

[Richard Skeen]

Thanks for all the suggestions so far.

I'll get some Plusgas tomorrow (I've only got WD-40 to hand) and cover it in that , hopefully it might soak through the fibre washer and into the threads. Then a combination of steady force while tapping the end of the spanner with a hammer.

If it still won't shift, the idea of cutting a new hole and fitting a new flange sounds like it could have potential. I couldn't find anywhere selling a 120/40 litre (1200x450mm) combination cylinder for much below

400 UKP.

Replacing the current combination cylinder + shower pump for a thermal store (DPS Pandora, Gledhill Pulsacoil, etc) might be nice, but the price seems a bit high, not much change from 1000 UKP I think?

I'll let you know how I get on.

Cheers, Rich.

[Dave Baker]

> So far I've tried: standing on one end of the tommy bar, levering up the

If it's stuck that tight it probably won't budge. Penetrating oil is unlikely to have any effect on limescale even if it could find a route past the gasket and through into the threads. Draining the tank and applying copious heat is a possibility. Copper has a high rate of expansion so if you heat around the outside of the boss and try unscrewing it while the immersion is still colder there might be some effect. In extremis you can drill and grind the thing away bit by bit with a dremel or high speed drill and a carbide burr but it wouldn't be a very pleasant job and getting the last bits picked out of the thread still wouldn't be easy. You might at least be able to make some entry holes for penetrating oil or in fact limescale remover which might be a better idea.

[John]

and almost everything.

[Harry Bloomfield]

Richard Skeen wrote on 04/04/2008 :

> So far I've tried: standing on one end of the tommy bar, levering up the

Last resorts....

Angle grinder, to cut the top off then you might find it is free - if not it should allow you to then get some Plusgas to soak down the threads.

If that still doesn't help, cut around the copper to remove the boss + element and buy a replacement boss to solder in.

[Ed Sirett]

1) Square up to the fact that you may lose the cylinder, I haven't as yet but there is always a first time, which it sounds like you may have already experienced. I've done about 10. 2) Try sharp knocks with the cylinder under full normal pressure, if you get lucky and it starts to turn then obviously you carry on without the water 8-) 3) If the heater is a top unit then you can drain the cylinder to below the top of the heater and apply a load of heat to the middle of the heater (the heater is finished right?) This may loosen the thread sealant so you can use a spanner. 4) If the heater is a lower unit you probably can't get the water out to do (3), unless you take the cylinder right out and put it on it's side.

[PeterK]

> So far I've tried: standing on one end of the tommy bar, levering up the

Faced with this problem once. Drilled an arc of holes round the inside of the element against the inner edge of the "nut" and towards the centre of the element and removed a "triangular" section. Then with padsaw cut through the element "nut" to remove an arc ( brass body so a little persuasion with a small chisel cracked it out). Drilled a second line of holes opposite the removed section and cut through the "nut". A few taps with a hammer on the remaining flats and the element was little more than finger tight. Ignored any issue (if there is one) with swarf dropping into the tank Of course I didn't have a Fein Multimaster then !!

PeterK

[Tony]

> So far I've tried: standing on one end of the tommy bar, levering up the

Richard, I had one stuck so bad once I bent the wrench trying to undo it. I found that by using a 3mm terminal screwdriver as a chissel into the side of the fibre washer, the washer could be levered out quite easily. Once the washer was out the immersion heater unscrewed easily. Good luck, Tony.

[nightjar]

> So far I've tried: standing on one end of the tommy bar, levering up the

If you have bent the cylinder, you ought to give up now and buy a new one. The distortion is a potentially weak point that could fail without warning. No doubt someone will have a story of having had a distorted cylinder for centuries, but the risk is still there. Aside from being the safest solution, it will be easier than trying to get the heater out and you will almost certainly end up with one that is better insulated.

Colin Bignell

[Richard Skeen]

nightjar If you have bent the cylinder, you ought to give up now and buy a new one.

Yes, it's bent a little round the immersion boss, so I should probably look at replacing it, especially since it's over 10 years old and very likely full of limescale. I've already bought the replacement immersion so if I can get the old one out there's less hurry to shop around for a cylinder.

I wonder how much scrap value I'll get for the old one, it's this sort of thing:

point about the insulation. This one has moulded-on foam which appears to be about 1.5" thick, but I can believe a newer cylinder may be better.

Thanks, Rich.

[crb]

I got =A310 from a scrap metal merchant for miy old cylinder last summer.

CRB

[Will]

Hi, I have come across "stuck" immersion heaters many times - I generally use 36" stilsons on a box spanner for the awkward ones, though that is not always successful, as my courage usually fails as the tank begins to bend. **

What I generally do then, though it takes a little time and is not particularly easy, is to use a hacksaw blade to cut out the fibre washer, after which the heater usually comes out easily. It is I believe usually where "boss white" or similar has been applied to the heater - against the advice of the manufacturers - that a lot of the problems occur.

**I have on a couple of occasions repaired resultant weeps by the application of solder, saving clients a considerable sum of money...