"T i m" wrote in message
...
On Thu, 06 Jan 2005 21:57:08 +0000, John Stumbles
wrote:



A separate valve and pump will give you a 'Power Shower', though the
term is also used for all-in-one boxes containing a pump + mixer valve
(thermostatic or otherwise). These look superficially like
electrically-heated showers i.e. a box about 300 * 200 with
knobs/switches on and a hose coming out the bottom.

Ah, yes, may have seen a bay of those in B&Q today .. .. so it would
go ..straight mixer, thermostatic, external pumped thermo, 'power
shower' (and electric)?

Not "electric" if I see what you mean. As John says "power shower" means a
pumped shower. The pump is either in a shower unit on the wall or (better)
separate. An electric instantaneous shower is something else, which runs of
the cold mains and heats the water in the unit on the wall, which means the
flow is very low by comparison. This and the wall mounted power shower look
similar but aren't the same. If you had another shower room, of course, an
instantaneous electric shower would be a sensible option there (if little
used) as it provides backup for when the other hot water system is broken.

Were you keeping the pump, thermostatic control would be an unnecessary
expense and complication. The bulk of the required thermostatic adjustment
in gravity fed showers covers effects from others opening hot taps etc. The
pump removes this problem, leaving changes in water temperature the only
thing you might want controlled. This is rarely a problem during the course
of one shower. If you are going to dump the pump later and run off a combi,
then you would need the thermostatic control. The flow from the combi would
be plenty for a shower but a pumped shower is likely to provide more flow.

I have a single lever Trevi shower driven by a pump which has been
excellent for many years (and is on its second pump).


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)