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Replacing immersion element

ted1

Generally is it much effort to unscrew it?

Tank is probably in since 84. Should be easy enough to unscrew or would you need to heat it.

What’s the chances of damaging threads or connections,

I understand it’s safer to loosen while fill as it helps stop the tank from moving if it’s a top element is there really need to drain it ?

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John.G

ted1 wrote: »

Generally is it much effort to unscrew it?

Tank is probably in since 84. Should be easy enough to unscrew or would you need to heat it.

What’s the chances of damaging threads or connections,

I understand it’s safer to loosen while fill as it helps stop the tank from moving if it’s a top element is there really need to drain it ?

If its a vented cylinder (with header tank) then shut off the cold supply water and just open a hot tap, this might leave a small amount which can be soaked up with a towel(s), the cylinder will still be full.

Make sure you use a proper "twin handle" removal tool so that, if room allows, you can apply a couple and avoid less strain on the cylinder.

I removed a 40 year old immersion (and reused it in a new cylinder). I couldn't
shift it first, so I got a sharp cold chisel and a lump hammer and gave the hex a few sharp blows in the anti clockwise direction to get it started, it came out easily after that without damaging anything.

K.Flyer

John.G wrote: »

If its a vented cylinder (with header tank) then shut off the cold supply water and just open a hot tap, this might leave a small amount which can be soaked up with a towel(s), the cylinder will still be full.

Make sure you use a proper "twin handle" removal tool so that, if room allows, you can apply a couple and avoid less strain on the cylinder.

I removed a 40 year old immersion (and reused it in a new cylinder). I couldn't
shift it first, so I got a sharp cold chisel and a lump hammer and gave the hex a few sharp blows in the anti clockwise direction to get it started, it came out easily after that without damaging anything.

This part is not advice I would advocate on a cylinder that you plan to keep using!
The immersion boss on cylinders have neen known to leak from aggressive removal of immersions and sometimes even less aggressive methods.
I, and many here, pre warn the customers of the risk of the immersion boss leaking before starting any work..

For fitting the new immersion it is very important to fully clean the surface and threads of the boss where the immersion screws into.
When fitting there is absolutely no need for ptfe tape or hemp etc.
There may only be a rubber ring on the new immersion, if so, you do not use anything just hand screw the immersion in the few turns until fully home, then pinch up tight with the spanner.
I am old school, I still prefer using a gasket on the immersion, no rubber ring, a good smear of uni-white on both sides of the gasket, a few dabs on the start of the threads, and in it goes, hand tight until fully home, then pinch up tight..

John.G

What method would you advise in removing it?.

K.Flyer

John.G wrote: »

What method would you advise in removing it?.

I have one immersion box spanner with an extended handle and another box spanner where I use a two foot stilson for leverage.
On a very rare occasion, a sharp strike or two to the stillson will shift a really stubborn one.
There have been only a small few over the years that have leaked, which is not bad out the hundreds of immersion units I would have changed.
But striking a sharp tool at the edge of the immersion would be too risky imo, one slip and you risk puncturing the top of the cylinder.

Wearb

Its also useful to tap it both clockwise and anticlockwise. I have seen plumbers heating them, but I was always afraid that I would disturb the boss weld.
Like KF, I wont go near them unless customer accepts that the cylinder might be damaged. Some cylinders in hard water areas will have become very thin around there anyway.

John.G

Wearb wrote: »

Its also useful to tap it both clockwise and anticlockwise. I have seen plumbers heating them, but I was always afraid that I would disturb the boss weld.
Like KF, I wont go near them unless customer accepts that the cylinder might be damaged. Some cylinders in hard water areas will have become very thin around there anyway.

Yes, I gave that a few taps clockwise initially but I was pleasantly surprised that it came out reasonably easily without beating it to death, mind you I had installed that immersion myself in 1972 using K. Flyer's method above and I only nipped it up.

I suppose it would be too much to expect cylinder/immersion manufacturers to make them with flanged fittings.

Wearb

I put a couple of wraps of ptfe on the threads to act a a lubricant (not sealer) ptfe is great at reducing friction. It makes it easier to tighten and remove.
The really difficult ones are the ones fitted with sealer on the threads.

ted1

This is the one I’m changing , any thoughts ?

signostic

You should by pass replacing the element and install a willis heater...much more efficicent and faster at heating water.
http://www.elemex.ie/external-immersion-heater/

Wearb

signostic wrote: »

You should by pass replacing the element and install a willis heater...much more efficicent and faster at heating water.
http://www.elemex.ie/external-immersion-heater/

While they have their uses, they’re not faster or more efficient than the regular in tank immersion heaters.

Wearb

ted1 wrote: »

This is the one I’m changing , any thoughts ?

Either get a plumber or follow suggestions above.

K.Flyer

ted1 wrote: »

This is the one I’m changing , any thoughts ?

Exactly the same as the one I changed a couple of weeks ago, it came out reasonably handy, but given it was probably in over 30 years, I let the long stillson do the work from the start.

One big gripe I do have about modern day immersion heaters, they do not last anywhere near as long as the older ones.

SCOOP 64

Wearb wrote: »

Either get a plumber or follow suggestions above.

What the rough cost of plumber supplied and fit?

ted1

Wearb wrote: »

Either get a plumber or follow suggestions above.

If I got a plumber the list of jobs would grow and cost me a fortune.

Replace old tank with insulated one , zone cylinder ( no way to Isolate it from rads), zone upstairs , replace some rads, power flush system, fit pump for shower, currently just use electric shower from cold tank.

I’d rather do the small jobs myself.

John.G

ted1 wrote: »

If I got a plumber the list of jobs would grow and cost me a fortune.

Replace old tank with insulated one , zone cylinder ( no way to Isolate it from rads), zone upstairs , replace some rads, power flush system, fit pump for shower, currently just use electric shower from cold tank.

I’d rather do the small jobs myself.

Just to go back to basics, are you sure that the element is "gone"?, it may be the rod type thermostat, if fitted, some of the older type immersions like my own did not have this type but had a "Otter Dualstat" type attached to the immersion top.
If you are happy that it is the element, then, as suggested above, can you not just try removing it by using judicious force! with that double handled socket or whatever and post back.

ted1

John.G wrote: »

Just to go back to basics, are you sure that the element is "gone"?, it may be the rod type thermostat, if fitted, some of the older type immersions like my own did not have this type but had a "Otter Dualstat" type attached to the immersion top.
If you are happy that it is the element, then, as suggested above, can you not just try removing it by using judicious force! with that double handled socket or whatever and post back.

You might be in to something.

ted1

I see otter written on the top , is that like a relay or how does it differ from an element immersion

John.G

ted1 wrote: »

I see otter written on the top , is that like a relay or how does it differ from an element immersion

I think it monitors the water temperature by just being in contact with the "boss" of the immersion and doesnt have a dip tube like the conventional immersion, my immersion, even older than your one has the change over switch on the top of the immersion but I only use it in Sink mode as I have a twin coil (oil/solar) 150 litre cylinder., it shuts the power off at exactly 60C, I dont think you will find any spares for them now but it would be interesting to ascertain where the actual fault in your one is.

The photo below was taken in a mirror reflection but there is only one red c/o switch.