Immersion heater removal

[peterb]

OK, any aspiring (or actual) plumbers out there....

My immersion heater in my hot tank needs replacing. The old one looks as if it has been in place for about 18 years and is stuck in. I have a large box spanner, and bent the tommy bar trying to shift it. I've squirted WD40 on it, and I've tried tapping opposing sides on the flats simultaneously with two hammers. I've tried hitting the tommy bar with a hammer in the hope the impuklse would shift it... it hasn't.

I have a sinking feeling that it might have been installed with thread sealer. I am now thinking about drilling a hole trough the base and using a hacksaw blade to cut through the threads. I don't want to use heat as it is an insulated tank, and copper is too easy to burn through anyway.

So any ideas?

[Agent]

I did mine recently. Although not as tight as yours, it was a bit of a pain to get off as well.

I had the same issue of the tommy bar bending (don't like that design at all). The solution for me was to use a box spanner that has a bar extending off it, like this:



I then hit that with a fairly big club hammer, which loosened it up very quickly. Keep in mind that with any 'shock' like this to the tank, you risk splitting it. A little unlikely as long as you're striking the tool, but take it easy at first and work your way up with the power of the hits.

You're welcome to use mine, but I suspect that the postage both ways would be the same cost as the tool Was under a tenner from B&Q.

Make sure you don't hit it the wrong way - you'll thread the tank and need a new one. Buy a replacement heater and check the thread on it if in any doubt, they're all standard.

[piggin23]

I remember my dad had problems with one of these (25+ years ago before they had the insulation moulded onto the copper work of the tank).
He tried everything you could think of (including heat) & he has been in heavy industry for all his working life, so knows a few tricks.
He gave up in the end & purchased a new threaded insert for the top of the tank.
He then cut a hole on the other side of the tank & brazed the new threaded insert into place.
The tank stayed this way (working without issue) until I changed the system a few years back for my parents (father was in his late 60s when I did this work).

So after this little preamble down memory lane, basically I think your

[peterb]

Agent, yes thought about the ring spanner, they seemed a bit flimsy, but worth a punt. The box spanner should have been OK, but it is a bit loose, I ended up having to 'chock' it with a shim on the flat.

I'll nip round to B&Q (or Screw fix) and see what they've got.

Piggin23 thanks - I think - just what I didn't want to hear!


Any other ideas?

[deejayburnout]

When I ran my own business I had to change a heating element and Unfortunately I ended up cracking the tank as I was applying that much force on it.

Ended up costing me best part of £800 to get a plumber to fit the new tank next day for the homeowner.

Doh.

Maybe you could try and apply some heat to the heater and hopefully the expansion might loosen it.

[piggin23]

As you said, not what you wanted to hear. (just looked at the price of a new one, not good)
I think you are right about the 'thread locker' on the heating element (plumbers love to slap this stuff around as they will never have to remove it again).
You can try to destroy the element in place & cut it away from the internal threads.
The only problem is, you could easily damage something (these water tanks aren’t very thick & can easily deform/bend if you put a lot of force into them).

[Agent]

Agent, yes thought about the ring spanner, they seemed a bit flimsy, but worth a punt.

Mine is solid. No flex in it at all. Wasn't expensive so you must have found a really cheap one!

[peterb]

Bit reluctant to apply heat to the copper - at least with a flame, and thats probably the only way as it is an insulated tank, and copper has a low melting point!

Ring spanner and hammer I think next. The tank is reasonably substantial ("they don't make them like that any more" ) so a bit og gentle persuasion with a hammer on the end of a solid ring spanner might be enough to break the grip. Once its started, it should be easy to do the rest.

Don't really want the faff (or expense!) of replacing the tank, although not that hard to do, although the chances of getting one with all the pipe fittings in the same place are remote, so there would be a bit of pipework to do.

But I hope it won't come to that!

[Agent]

Just make sure it's empty, or at the very least you've drained enough out and stopped any incoming water

[peterb]

Just make sure it's empty, or at the very least you've drained enough out and stopped any incoming water

Oh yes!

[peterb]

And spent yesterday afternoon tapping at the ring spanner (like the one in Agent's post) with a hammer - without any effect. I resisted the impulse to get a larger hammer on the basis that a number of small blows with a smaller hammer would break the corrosion (or whatever) on the threads without wrecking the tank, whereas a large blow with a hammerhead of greater mass is more likely to tear the tank/boss.

So to plan B (when I have thought one up).

[Agent]

So to plan B (when I have thought one up).

Hit it harder

I had to hit mine *really* hard for it to move. The problem is, no matter what method you choose, it'll need to be unscrewed so you can put the new one in. Unless you want to make a new hole for the second one.

You also don't want anything to get into the tank. I had a tiny bit of insulation fall in and has made it's way to my taps in the kitchen, vastly reducing the hot water taps flow. I keep meaning to sort it but I've not got around to it yet.

If you don't want to add heat, have you considered freezing it? Go and grab some pipe freezer from Screwfix / wherever, make it as cold as possible, and then hit it.

[peterb]

Hit it harder

I had to hit mine *really* hard for it to move. The problem is, no matter what method you choose, it'll need to be unscrewed so you can put the new one in. Unless you want to make a new hole for the second one.

You also don't want anything to get into the tank. I had a tiny bit of insulation fall in and has made it's way to my taps in the kitchen, vastly reducing the hot water taps flow. I keep meaning to sort it but I've not got around to it yet.

If you don't want to add heat, have you considered freezing it? Go and grab some pipe freezer from Screwfix / wherever, make it as cold as possible, and then hit it.

True, might need to get the lump hammer out! I tried some freezer spray, but probably didn't make much of a difference. Certainly not going to make another hole! I do have a gas powered hot air gun, so that might be worth a try if I can direct the heat away from the insulation.

One option (of very last resort) would be to drill a hole in the immersion base and use a hacksaw blade or alligator saw to cut a couple radial cuts to the edge of the the threads.

The immersion is working, but it is at least 15 years old, and I can tell from the noise it makes that it is heavily furred up - the`plan is/was to fit a titanium sheathed one, so the plan of last resort really is one of no return - and only really worth it if the immersion element had failed.

[Funkstar]

Just had a look at them online to get an idea of their shape and construction.

I would be tempted to take the top off and start dismantling it from the inside. If you were able to take the elements out from where the cap is, you could get an idea of what is ceasing it. Perhaps even do a fully destructive removal after that.

[RobbieRoy]

I have done this on one or two tanks in the past - an old trick is to extend the length of the lever turning the immersion spanner by placing a piece of pipe over the end of it - saves having to welly it with a lump hammer!

However, it's not always possible as some really won't move without busting the tank, in which case tap the tank side and fit a new element in a different position - a decent plumber won't charge much for that.

Good luck!

[peterb]

Just had a look at them online to get an idea of their shape and construction.

I would be tempted to take the top off and start dismantling it from the inside. If you were able to take the elements out from where the cap is, you could get an idea of what is ceasing it. Perhaps even do a fully destructive removal after that.

The element drops down, and is usually braised in place, so it can't be dismantled in situ.

I have done this on one or two tanks in the past - an old trick is to extend the length of the lever turning the immersion spanner by placing a piece of pipe over the end of it - saves having to welly it with a lump hammer!

However, it's not always possible as some really won't move without busting the tank, in which case tap the tank side and fit a new element in a different position - a decent plumber won't charge much for that.

Good luck!

I tried extending the tommy bar on the box spaner - just bent it! It wasn't a particularly good fit anyway, the ring spanner is better.

It isn't just tapped into the tank (they are quite thin) There is a threaded boss braised into the tank at manufacture (before the foam insulation is applied. I'm leaving it for the moment, although I discovered a friend of mine has a pipe freezing kit (proper one, not an aerosol version) so I might see if I can borrow that and try to shrink the immersion heater body a bit to break ny sealer that the original fitter used.