Boring Plumbing Question - Immersion Heater Removal

[Tony]

Apologies in advance for the boring nature of this post - but has anyone ever successfully removed an immersion heater from a hot water cyclinder? Having sprayed liberally every day with WD40 every day for over a week, I was hoping it may come out easily. Seems like that was wishful thinking...

So far, I have very successfully folded over the lever arm on the box spanner I bought from B&Q. Given I am a bit of dweeb, I was quite impressed by that. So I replaced it with some 10mm threaded rod - but that was even weaker and I've bent that too. 12mm threated rod seems stronger - but is too big to go through the holes in the spanner.

Anyone know if immersion heaters come out more easily if the tank is hot or cold? Anyone done this before without damaging the hot water cyclinder? I guess the cyclinder and immersion heater are both about 15-20 years old, so maybe it would be cruel to separate them after all these years....

[-Adam-]

Why are you trying to take it out?

I would have thought though, that it would be easier to remove when the system is cold, as while hot it's all slightly expanded.

If the system is that old though, it's probably all corroded together, way beyond the help of WD40!

[Steve B]

Hi Tony, you may have to get your drill out for this one . If you put too much force into removing it with a spanner, you will probably split the tank around the thread and that will be the end of the tank.

Get your drill, put a new sharp drill bit in it, and drill a series of holes around the immersion, just inside the thread. This will enable you to remove the immersion leaving only the thread, which will collapse with the aid of a hammer, screwdriver and possibly a hacksaw . Job done

This is always a last resort but that seems to be where your at now... Good luck, it will work.

[huw williams]

This is more like it... there's not enough plumbing, car-maintenance or weldng tips on this forum, real man's stuff unlike that leg-shaving debate.

Anyway, Tony any chance I can send a camera crew round when you try this....?

[quote="Steve B"] Get your drill, put a new sharp drill bit in it, and drill a series of holes around the immersion, just inside the thread. This will enable you to remove the immersion leaving only the thread, which will collapse with the aid of a hammer, screwdriver and possibly a hacksaw . Job done .

[Andrew G]

Top tip Steve as anything that lets you play with a drill, pretending it's a gun obviously, and then whack things with a hammer is always worth doing.

I'd call a plumber.

[BrendanM]

IMPORTANT INFORMATION

When trying to remove the immersion heater make sure that the tank is under pressure.
The pressure helps to prevent damage to the tank. If you are not careful you could twist the flange of the [relatively soft] tank.

Secondly, when you apply the tension to the spanner simultaneously tap the body of the immersion heater with a hammer or other metalic object. The vibration helps to loosen it, not the brute force. Tap it but dont bash it.
If you can't tap the heater then tap the ring of the spanner.

good luck.

[Snoop Doug]

my plumber tried to remove my immersion recently... no this is not the home sec'y husband speaking...

First, he hit it with a hammer
Second, he heated it up
Third, he hit it with a hammer
Fourth, he heated it up

Y'know, it's funny but I've heard of a kind of film genre that's kinda repetitive in a similar way...

Anyhoo, in the end it all went off bigtime and I had to get a new one - sorted

[George]

Also Try using a BOX spanner rather than a normal immersion heater spanner as you can get more leverage maybe even put a longer bar through a couple of holes in it.

[BrendanM]

If you try my method the tank will start to leak when you start to free off the tight immersion heater.
You could put adjacent pencil marks on the tank and heater before you start to undo the heater so that you know if it has moved or not.

When you know that the heater has started to move, remove the water pressure before undoing the heater completely.

There should be a valve which shuts off the water supply into the hot water tank. You don’t want to drain the header tank [which is often installed] above the hot water tank if you can ovoid doing so.

Oh, and make sure the heater is disconnected from the electrical supply!!

[mrP(Boonen)VT]

[quote="George"]Also Try using a BOX spanner rather than a normal immersion heater spanner as you can get more leverage maybe even put a longer bar through a couple of holes in it.

[Tony]

Thanks to all for the advice. Seems like we have some plumbing exertise in the club....

I'll have another try in a few days.....using the Bredan method. I had already tried to 'shock' the heater to persuade it to come out by hitting it with a hammer - but I shall try again - with the tank under pressure. Failing that, as Steve suggests, it may be a job for the drill.

Like many DIY jobs, it was all going so well....tested the thermostat - it seemed fine, so heater itself must be broken, disconnected the electrical supply to the heater, isolated the water supply to the hot tank easily (the tap in the loft turned straight-off), drained off a bit of water from the hot tank via the drain-cock on the supply at the bottom of the tank (which opened and closed again without any drama), even had some spare garden hose in the garage to help. It was all going so well... I will try again when I have a bit of time to spare.

Huw - glad you appreciate manly debates on this forum. I bet you never knew that a Reebok Gymball can assist with the removal of an immersion heater? Well, it would have done, had I managed to get it out. Or that old inner-tubes can assist with erecting gate posts....

[BrendanM]

Immersion heaters have an electrical heating 'element' which should be electrically continuous.
You could test it with a test meter if you have one.
Some heaters have a thermal safety switch incorporated in the design to prevent overheating if there is no water in the tank. They sometimes have a long probe and look like the electromechanical probe thermostats.
If the safety switch is faulty the heater wont work.

[Marky Mark]

[quote="BrendanM"]Immersion heaters have an electrical heating 'element' which should be electrically continuous.
You could test it with a test meter if you have one.
Some heaters have a thermal safety switch incorporated in the design to prevent overheating if there is no water in the tank. They sometimes have a long probe and look like the electromechanical probe thermostats.
If the safety switch is faulty the heater wont work.

[Marky Mark]

V = I / R.

Roughly speaking and it wont be far off.

V / A = Ohms

Thus 230/13 = 17.7 ohms on your multi-meter

[Snoop Doug]

So Tony - how'd it go then? Jiminy, am I the only one in suspense update please?