HI Tony

On Fri, 23 Mar 2007 18:29:55 GMT, Tony Bryer
wrote:

On Fri, 23 Mar 2007 15:25:13 -0000 Donwill wrote :
Polite suggestion---- These things can be DANGEROUS and can EXPLODE, If you
don't know how to proceed, then DON'T, get someone in who is familiar with
the installation of electric under-sink heaters.
They are meant to be installed with an open vent tap which are very
expensive, the water expands when heated and drips out of the open vent
tap, the outlet is always open and the tap controls the inlet side of the
heater, I recently purchased a tap for my heater which cost me approx £90.

I will agree about the potential for danger but in many cases you no longer
need an open vented tap. The requirement is either for an expansion vessel or
for a suitable length of pipe between the heater and incoming main. You also
need a safety valve.

OK - thanks....

The heater came with a little safety valve.
The instructions require that a 'T' untion be fitted to the cold
inlet. One end of the 'T' goes to a drain valve, other end goes to the
safety valve, and then on to the incoming water mains 'via a flexible
pipe'.

In my case, the water 'main' is fed from a private deep-bore well,
with a pressurised expansion vessel - situated about 12 feet away as
the pipe runs.

Wonder if this sounds suitable ?
The installation is in a timber Studio - I was planning on installing
the safety valve outside the building (freezing isn't going to be an
issue - we're in South-West Ireland) - the valve can then 'leak' to
outside, if it needs to.

The current pipework to the well is 3/4" black Alkathene, so I was
going to tee from that into the water heater, also fit an additional
tee before or after the safety-valve to feed the cold tap on the sink.

I've a fair bit of (amateur !) experience in plumbing & wiring - but
this is the first time I've come across one of these devices - and I'd
like to get it right g

Regards
Adrian