"Martin Angove" wrote in message
...
In message 2UKkc.18$XV3.1@newsfe1-win,
"Franglais" wrote:

We would like to install an electric power shower in our bathroom. The
location is on the wall of the cupboard where the hot water tank resides
with pipes right behind the wall and high wattage electric to the
immersion
heater.

Would this be a major plumbing job? DIY able? If we got a Plumber in
what
would the ball aprk cost be?

£150 - £300

Do you mean a pumped shower (i.e. using stored hot water), or an
electrically heated shower?

Electrically speaking, in either case you will not be able to use the
supply to the immersion heater in order to feed the shower. The
immersion should be powered from its own circuit, probably be fused at
15A or 16A for a heater rated at perhaps 13A (3kW). In theory this would
allow you to attach a small load such as a shower pump, but the IEE
doesn't like it and specifically says that fixed heaters such as
immersions should be supplied from their own dedicated circuits. The
supply to a pump is quite small however and can quite properly be taken
from a spur on your sockets circuit.

If you mean an electrically heated shower then these take a *lot* more
power than an immersion heater and are fed from their own dedicated
circuit, usually rated between 30A (7kW) and 45A (10kW). They must also
be fed via an RCD.

In the case of a shower pump, the electrical work is relatively easy and
probably quite minor assuming the ring circuit isn't too far away from
the location of the pump. In the case of an electrically heated shower
the need to run a hefty bit of cable (6mmsq or 10mmsq) and to provide a
suitable supply will make the electrical work much more onerous.

Either will require the supply to be protected by an RCD.


As for the plumbing, electrically heated showers just need a good cold
feed. Pumped showers may need a bit more, but plumbing isn't my strong
point. There have been several threads here *very* recently (in the last
fortnight or so) containing advice on this issue - search for "essex
flange" and you should turn up several interesting discussions.

If your cold water storage tank is in the attic a floor or so above the HW
cylinder you probably don't need an Essex (or other type of) flange but can
simply take your hot water feed from the pipework low down e.g. tee off from
the feed to the hot tap of the bath or basin. The cold water supply will
need to be from the tank in the attic too and if there isn't currently a
tapping on that tank for this (i.e. if the bath's cold supply is direct from
the mains) then you'll need to arrange the supply from a separate tapping on
the tank. This tapping should be an inch or so lower than that feeding the
hot water cylinder, but still a couple of inches above the bottom of the
tank. You may have to swap over the hot and (new) cold tappings to achieve
this.

It's not a major plumbing job, but can be a bit fiddly. 'DIY-able' depends
on your skills, resources and experience: if you've only ever put up shelves
you'll probably have trouble, if you've fitted a WC or changed taps at the
back of a sink or bath you'll probaly find it OK.