"Andy Hall" wrote in message
...
On Mon, 07 Nov 2005 09:45:54 +0000, Steve Gouldstone
wrote:

My hot water tank has wiring for an immersion heater, but one isn't
fitted. The tank, I would guess is about 20 years old.

Is the fitting standard - ie can I just buy an immersion heater and be
sure it will fit?

Thanks

Yes they are as long as there is a removable plug. You will need an
immersion heater spanner.

Tip: It is safer to undo the plug using the spanner and tapping it,
than to pull the spanner continuously. The copper is less likely to
distort.

The heater should come with a fibre sealing washer, but some sealant
such as Boss White or equivalent is needed for the threads.


NOT on the threads Andy - it sets like concrete! With an immersion heater
the seal is between the flat face of the immersion and the face of the
cylinder boss where the fibre joint is located. A light smear of compound on
these faces to assist the fibre joint is all that should be required. I put
a couple of turns of PTFE on the threads not as a seal but as a lubricant so
the immersion can be removed later if required, without destroying the
cylinder