Not that long ago the shower in my house was very good. It was an
Aqualisa thermostatic controlled mixer shower, probably 20 years old
but it provided a very good shower. The the problems started and the
pressure fell away so that the shower was poor. I thought it was the
showerhead so I de-scaled it, but with no improvement. I then changed
the head and hose, still with no improvement. Then I took the control
valve apart, cleaned it and having found no obvious problems put it
back together again. However, this shower which had previously been a
good hard flow remained a sluggish drizzle.

Thinking that the valve was shot, I replaced it with a new thermostatic
valve (Triton Izar). Still no improvement. Sincle then I have done the
following:

Replaced hose with large bore hose .
Replaced inlet connecters with 22mmto 3/4in bsp (was 22mm to 1/2in
bsp),
replaced isolation valves with new full bore lever valves.
Drained and flushed all pipes.

The shower is fed from a gravity cold tank about 1.8 meters above the
shower head and an oversized hot water tank, both through dedicated
22mm pipes. When I flushed the pipes the pressure was enough to
produce jets the length of the bath, so flow and pressure seems ok to
me.

I am now at a loss to see what is causing the low pressure in the
shower. It used to be ok, but now is not. Is this a problem with the
Triton shower, or should I raise the header tank ?

You already have a more than adequate head of pressure above your shower
head,is the drizzle on both hot and cold .Is your pipe work balanced i.e. do
you have a dedicated cold supply to the shower straight from the cold tank.

Yes both both and cold come in their own dedicated 22mm pipes. Both
produced a 4 ft jet accross the bath when I flushed the pipes.

Is there a valve on the hot water supply (probably somewhere near the
hot water tank) which has been partly closed for some reason?
If so then the hot water flow will be reduced and since you have a
thermostatic shower this will reduce the cold flow to keep the
temperature up.

Thank you for that thought, I will check, any other suggestions ?
What about a different shower mixer, is there a thermostatic valve
which works well for low pressures ? I need an exposed model.

Does the tank supplying the shower need an air inlet ? If so and it
has become blocked then the output pressure would drop.


On 15 Nov 2005 12:23:12 -0800, wrote:


Not that long ago the shower in my house was very good. It was an
Aqualisa thermostatic controlled mixer shower, probably 20 years old
but it provided a very good shower. The the problems started and the
pressure fell away so that the shower was poor. I thought it was the
showerhead so I de-scaled it, but with no improvement. I then
changed
the head and hose, still with no improvement. Then I took the
control
valve apart, cleaned it and having found no obvious problems put it
back together again. However, this shower which had previously been
a
good hard flow remained a sluggish drizzle.

Thinking that the valve was shot, I replaced it with a new
thermostatic
valve (Triton Izar). Still no improvement. Sincle then I have done
the
following:

Replaced hose with large bore hose .
Replaced inlet connecters with 22mmto 3/4in bsp (was 22mm to 1/2in
bsp),
replaced isolation valves with new full bore lever valves.
Drained and flushed all pipes.

The shower is fed from a gravity cold tank about 1.8 meters above the
shower head and an oversized hot water tank, both through dedicated
22mm pipes. When I flushed the pipes the pressure was enough to
produce jets the length of the bath, so flow and pressure seems ok to
me.

I am now at a loss to see what is causing the low pressure in the
shower. It used to be ok, but now is not. Is this a problem with
the
Triton shower, or should I raise the header tank ?

Tried all these tips this weekend, no success. The other hot taps all
flow quickly so I don't think it is the venting to the hot tank. ALl
the stopcocks that I can find near the tank, and on the way to the
shower are onn full, so it's probably not that. Could it be the shower
valve ? Does a Triton Izar have a flow regulator in it ? Would a
mixer valve with no thermostatic control produce a better flow, or do I
need a specialist valve for low pressure ?

Funnily enough I have exactly the same problem with our Matki shower.
I am going to phone them up and find out what the issue may be. We are
going
to fit a mains pressure system at some point in the future anyway
but I am still curious to know... I think it is related to the
thermostatic
nature of our new shower.