Immersion heater replacement?

[Marnhullman]

My daughter's flat has a combination water cylinder with an immersion heater. The heater does not work and needs replacing but so far I have been unable to unscrew the old unit. The spanner I'm using carries a warning about not using undue pressure as the cylinder may distort or even break around the heater boss. I've tried spraying WD40 around the thread but there is a fibre washer between the heater and the cylinder that I suspect is soaking it up so the thread is still stuck.

Does anyone have any tips as to how I may free up the old heater?

My daughter is resigned to the fact that she may have to replace the cylinder as well but money is very tight so if I can replace the old heater that would clearly be preferable.

In the top of the section of the cylinder is what appears to be the remnants of a circular pipe. The thing is in several pieces and is covered in scale. I think it's a sacrificial anode? Due to its current condition I can't tell how it was fixed into the cylinder but there seems to be a short section of pipe poking up from the base of the cylinder. A local plumbers merchant said he would just leave it as it is and anyway he doesn't stock replacements. The cylinder is 18" diameter.

If it is a sacrificial anode must it be replaced i.e. will great harm be done if I don't and if it must be replaced where can I get a replacement?

Thanks

 

[kevplumb]

you have drained the cylinder first (havent you)

 

[oilman]

Best tool I've come across is a cast iron spanner. You hit it with a hammer, usually shifts it (I've not had a problem yet).

 

[kevplumb]

failling that heat the boss

 

[oilman]

Easily done by asking for an excessive pay rise.

 

[kevplumb]

ours is growling already and the jib rate hasnt gone up yet

 

[Nemo]

Snowsride - if u live in an area with hardwater, a build-up of limescale will seal the immersion in good and tight.

You are correct to be concerned about applying to much pressure as this could rupture the wall of the cylinder = new cylinder....

Try to heat the area around the immersion fitting as this will remove a lot of the limescale and should make it easier to undo - HOWEVER YOU MUST REMOVE a section of the insulation material around the immersion fitting FIRST. Use a stanley knife or something similar to cut out a 10 - 15 cm sq piece of material which u can then tape back once completed.

Good luck

 

[Marnhullman]

Nemo & others

Thanks for the advice - will try heating up the boss.

Still a bit concerned at the loss of the sacrificial anode in the cylinder - will the new immersion heater immediately start to corrode and quickly fail?

 

[RandyMarsh]

...although my problem is with the screw in cap that you need to take out of the cylinder to put in the immersion heater. I just cant shift it!

Tried heating up the boss,

even tried getting a pair of stilsons around it and hitting those with a hammer,

...nothing seems to work.

I'm worried I'm going to damage the cylinder. I think I already have bent the boss inwards a bit (if that makes sense).

Any suggestions would be greatly appreciated!!! Cant really afford a new cylinder at the moment!

 

[HERTS P&D]

Use a box spanner, I haven't found one that won't undo. How did you apply heat?

Andy

 

[Nige F]

so it`s a horizontal immersion @ the bottom of the cyl ? _ for these you drain the water then hold a blowlamp on the face of the immersion until the fibre washer goes BANG . then you can unscrew the immersion - done dozens like that For a top ( dome) mounted immersion it`s a different procedure.

 

[Nige F]

...Tried heating up the boss,

).

Any suggestions would be greatly appreciated!!! Cant really afford a new cylinder at the moment!

HEAT it don`t just hold your zippo under it

 

[RandyMarsh]

Eh I have man! Held my torch on it for a good while. Might try and get someone else to hold the torch while I try and turn it? What do you reckon?

 

[JohnD]

there is a method involving drilling the immersion heater head, and sawing towards (but not through) the screw thread, so that when you put the spanner on it, the head collapses and goes loose. Who's got the links to the photo?