"Tim Mitchell" wrote in message
...
In article , IMM writes

"Andy Hall" wrote in message
.. .
On 13 Aug 2004 04:28:33 -0700, (armitageshanks)
wrote:

Hi,

Can someone help?

I have installed a mixer shower in my bathroom assuming the cold tank
in the loft above the bathroom and the hot tank in the bedroom next to
the bathroom would all be in the right places to provide a decent
shower.
How wrong was i????????

I have a really nice looking shower with a really annoying dribble
effect?
I have heard that you can get shower pumps to boost the water pressure
which connect onto the hot water cylinder.

Can any kind person confirm whether this will improve the rate at
which the water is forced out, and also and recommendations would be
appreciated.

Thanks,

Nigel

Yes it will do as long as the plumbing is done correctly.

The important thing is that 22mm pipes are used throughout, especially
on the input side of the pump. You can perhaps do the last metre or
so to the shower valve in 15mm if needed.

Shower pumps do not like sucking.
Preferably install the pump in a location such that the main runs of
pipe are on the output side for this reason.

Also, install the pump relatively low. The airing cupboard floor is
usually a good bet. The loft is not.

Nothing wrong with the loft as long as the pump is on the loft floor
below
the cold water tanks water level and the inlet pipe goes back to the
cylinder, not teed off the open vent pipe.

The problem is, that will put the pump at a high point in the pipework
and it will keep getting airlocks in the hot side. At least, ours did,
if I did it again I would install the pump low down.

I've done it both ways and can confirm that having the pump a few feet lower
helps. It was on the loft floor, as also was the cw storage tank: it
mightn't have been so bad if the tank had been a couple of feet higher up. I
then moved the pump into the airing cupboard; not on the floor of the
cupboard (there wasn't enough room) but on the first shelf above the
cylinder, and it works much better there. As I recall the problem was that
the flow switches didn't always kick in at some settings of the mixer valve
and sometimes the pump would run intermittently. This may have been caused
by air getting trapped in the pipework but I didn't think of a way to
determine that for sure.

The hot feed is taken off the hot distribution pipework somewhere around the
bottom of the airing cupboard and the cold feed from its own tapping from
the cw tank. All pipework is in 15mm plastic. With all respect to Andy[1] I
wouldn't go for 22mm pipework except, possibly, I had a very long run on the
input side and/or the pump was mounted high up wrt the tank.

The pump I'm using is a Watermill with LV transformer which cost about £180
(IIRC). The only reason I used that is I already had it left over from
another job. I haven't used Stuart Turner pumps but expect they might be
quieter and possibly last longer than cheaper ones (spares are available for
Watermill too, though not for some other cheap makes). Mounting pumps to
keep the noise acceptable is a bit of a black art.



[1] coz he's bigger than me ;-)