weak power shower

Forsh · 10 Jul 2007

I've installed a 1.5 bar pump under my hot water cylinder, the cold tank is above in the attic both connected with 22mm pipe reduced at the pump to 15mm inlets.
the shower is back to back with the airing cupboard, 2m max from pump to shower, each outlet (15mm) passes through a 90 degree elbow, the mixer valve, a 90 degree wall plate elbow, 90 degree outlet elbow and the handset.

the result is a shower comparable with the mains supplied electric shower in the main bathroom rather than being pinned to the floor in a torrent of hot water

is there a right angle too many or do i need a 2 or 3 bar pump?

Cheers

Dan Robinson · 10 Jul 2007

Have you put a decent shower head on?

Have you connected to the cylinder correctly?

Forsh · 10 Jul 2007

Thanks for the reply

The shower head is pretty standard 3 mode head

the hot is tee'd into the 22mm feed from the top of the cylinder at a point just lower than the bottom of the cylinder - maybe not as good as a dedicated feed from a surrey flange connection - I haven't tried it with anything else turned on but even with everything bar the shower turned off its still a lack luster power shower

I've since had a look at the Salamander web site and I think the pump may have been the wrong choice and 2.25 or 3 bar would deliver the invigorating shower I was hoping for!?!

Dan Robinson · 10 Jul 2007

You could also try installing it correctly.

Forsh · 10 Jul 2007

as opposed to...?

as i understand it teeing into this pipe is not incorrect - its effectively 22mm from cylinder to pump

corgiman · 10 Jul 2007

Forsh said:
as opposed to...?

as i understand it teeing into this pipe is not incorrect - its effectively 22mm from cylinder to pump

It is incorrect as it could pull air and give you TUM TUM TUUUUUM poor pressure

both hot and cold feeds should have their own independant feeds, IE cold a new tank boss and the hot on a surrey (or if you ae a flash wotsit Essex) flange

Forsh · 10 Jul 2007

fair enough, but the cold is a dedicated line and there is no change in shower operation when turned to just cold

Gasguru · 10 Jul 2007

Did you flush all the pipework - perhaps the filters in the pump and shower are clogged( if fitted).

Are you using speedfit pipe and fittings - these can be restrictive.

Some showers are designed for very high presures so your pump may not be adequate - check the technical specs.

Forsh · 10 Jul 2007

Gasguru said:
Did you flush all the pipework - perhaps the filters in the pump and shower are clogged( if fitted).

I haven't checked but will do

Gasguru said:
Are you using speedfit pipe and fittings - these can be restrictive.

Yes, between the pump and flexibles (13mm bore) connected to the shower but as the runs are fairly short I'd have thought the pipe work after the mixer would be the worst case (wall plate elbows)

Gasguru said:
Some showers are designed for very high presures so your pump may not be adequate - check the technical specs.

this is what I'm thinking but posted the initial question to check if all else is ok - there are issues but I'm not convinced they add up to enough to cause the problem

Dan Robinson · 11 Jul 2007

but the cold is a dedicated line and there is no change in shower operation when turned to just cold

That could just be the shower design; but see other posts first.

Certainly run the hot correctly - there are a miriad of threads on this recently.

Your bends should not be a problem.

Also, (depending on make and model) it may just be a cr@p pump.

Have you actually measured the flow rate through the shower without the head attached? Has the head got scaled up?

simond · 11 Jul 2007

What is the make and model of shower.

If it is a thermo then basic models have reduced waterways to restrict flow, allowing a cheapo slow reaction time cartridge to shut off the water before a large volume of hot has passed.

The better thermo showers have a faster cartridge and therefore are designed to permit a better flow rate.

Forsh · 11 Jul 2007

the area is a soft water area so no problems with limescale

I fitted the pump a while ago but only just finished the ensuit so I'll have to check the plumbing but I'm pretty sure the reason I didn't use a surrey flange was because the cylinder doesn't have a threaded boss at the top

the shower valve is a simple mixer - not thermostatic

the pump was sub £100 from screwfix (like this:http://www.argos.co.uk/webapp/wcs/s...1&referrer=FG13P&engine=froogle&storeId=10001 )

I'll remove the shower head to night and try to measure - any tips?

thanks for all your replies

Forsh · 11 Jul 2007

I've just found the showerforce installation guide...

http://www.showerforce.com/ntpages/404-0504.pdf/$FILE/404-0504.pdf

page 3 shows the hot tee'd into the hot pipe as i have installed it

would i be correct in saying this may be ok for a small pump but could cause prombems as you up the flow rates/pressures?

Dan Robinson · 11 Jul 2007

I don't want to be too rude about the pump; but I have never seen a manufacturer say that fitting it off the cylinder the way you describe would be OK. I am surprisede they do; they also mention an Essex Flange - that would be a better method IF you can't fit a Surrey flange on.

Your cylinder will have a threaded tapping at the top - again I've never seen otherwise.

Bon · 11 Jul 2007

There is nothing wrong with teeing off the hot pipe to go to the pump, provided it's below the tee that goes up to the open vent.

In an ideal world you should use one of the aforementioned flanges however replacing an existing cylinder outlet to get a Surrey/York flange on can be an arse and Essex Flanges are easily dropped into the cylinder.

The only problem I have found putting a pump in like this is that if a hot tap is run for a while, the pump may chirp on when the tap is turned off however this is easily solved with a check valve.

I would put money on there being a blocked filter somewhere in the system that's causing the flow problem. You certainly don't need a higher pressure as there's no way you've got 1.5 bar resistance in the pipes to the shower if they are 22mm (1.5 bar = 15m of vertical height!!)

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weak power shower

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