Poor Shower pressure - Unvented System

[elbitrevnoc]

Can anyone help me with some ideas on this? I am completely non-technical when it comes to plumbing, but we have just had an Ariston unvented cylinder installed following a loft conversion.

My problem is that pressure/flow to the all the house taps seems fine, but the flow to the showers is not that good and turning on a bath tap in one bathroom will bring the shower in another to a virtual stop. We have three showers - An Aqualisa quartz in the master en-suite, a shower in the loft (unknown make) and a Tre Mercati shower valve set-up over the bath in the family bathroom. The Tre Mercati probably performs the best, but the en-suite and loft are the worst - probably about 10 litres per minute!

My plumber suggested that the problem is my existing Kinetico water softener, but we have 22mm converter kit installed and, whilst I accept that the flow IS slightly reduced with the water softener engaged, the pressure remains very strong at all the taps and the showers remain the only problem. In any event, the showers are poor even with the softener completely disengaged from the system.

I know that pressure into the house is v good (sorry, I don't know exactly what it is), but, even if this was a problem I would have thought we would have a problem throughout the house - not just the showers.

Any ideas would be greatly appreciated as my plumber appears to be washing his hands of the problem!

 

[gas4you]

Sounds as if the problem could lie in the pressure reducing valve as the showers should have had the cold taken off after this.

It could be worth stripping this out and checking there is no debris blocking it from the installation

Either that or your flow rate from the cold mains is not as good as you think.

Is your cold mains from the street at least 25mm and 22mm all the way to the unvented cylinder?

Is your stop cock fully open?

 

[elbitrevnoc]

Thanks Dave. So far as I know the cold mains supply is all at least 22mm and I am assured that the system has been checked for debris, etc. I don't know about the pressure reducing valve and where the shower supplies are taken from, but will get this checked out. Stop cock is fully open.

I will let you know what progress we make.

 

[leakydave]

Are any filters in the shower itself blocked?

 

[elbitrevnoc]

A quick update! We're still struggling with this and original plumber seems to have washed his hands of the problem. I'm now looking to get another opinion elsewhere. Rate of flow at the garden tap is 30 litres per minute and pretty good. I accept that the Kinetico water softener does slightly reduce the flow, but this does have a highflow kit fitted. In any case the flow is still not good enough even if the water softener is disengaged.

The Aqualisa Quartz shower now defaults to boost all the time, which is just as well as flow is at least passable with boost engaged! I don't understand why this has happened - before we would choose to engage boost in order to compensate for the poor flow, but this no longer happens. Does the Quartz shower default in this way if water flow is insufficient? We also now have a pretty bad water hammer problem from the expansion tank and hose - this happens when the water is run first thing in the morning or evening. Someone did suggest positioning the tank differently (i.e. on its side), but this has made no difference.

To be honest it's driving us mad. We now have three showers, but objective of having these is rather defeated if you can't run two at once! Any good unvented specialists in the Reading area???

 

[nogoodatfaultfinding]

Have all the showers got their own dedicated run from the cylinder?
if not they really should have!!

 

[elbitrevnoc]

Thanks. Good question! I'm not sure of the answer, but I suspect not. Could you explain the pros & cons a bit more please? Why, for example, would this have an adverse effect on shower flow if nothing else was turned on?

 

[nogoodatfaultfinding]

If there are to be showers, bidets or monobloc taps in the installation then a balanced cold supply is necessary.
There is a 22mm balanced connection on the inlet control set.
But the best setup method is to spit the inlet control set on to two parts. Site the pressure reducing valve immediately after the incoming cold mains stopcock (typically under the kitchen sink.) All outlets in the house will be at 3 bar and automatically balanced, otherwise they will constantly try and share the same 3 bar pressure(for example) and thus lose pressure at every outlet.

 

[nogoodatfaultfinding]

if i could draw a picture of what i know is in my head then i would but i cant.
Easily put it is always best practise to give any shower on any system its own dedicated run.

 

[nogoodatfaultfinding]

Imagine that but with 2 x tees coming out at the outlet one each for the other showers then i beleive that is the setup you require for best practise and effiancy.

 

[elbitrevnoc]

Thanks nogood. I appreciate your effort on this and will investigate further. Will let you know!

 

[steve32]

what is the flow rate l/m at outside tap with 2 taps working cold kitchen and outside tap
and working pressure at outside tap with 2 taps running
i assume the stop valve on incoming water supply is 22mm and 25 or 22mm coming into house was incoming main 22 or 15 if 15 has it been replaced under ground

the aqualisa quartz showers for unvented systems do not have a boost control they have on on/off button only
is this the pumped shower the pumped shower will have a twin button
if you have the pumped shower it will require changing to the standard quartz shower
you can replace the complete unit or the control button and the processor unit approx £300 + v.a.t for parts
if you have a pumped unit it must not be used on an unvented cylinder

i have recently installed a a 210l unvented cylinder running 2 showers, bath 4 basins kitchen and utility sinks the working pressure was 3bar and flow 15l/m with 22mm main into house
as this is not a suitable pressure and flow for the outlets we also installed a 300l accumulator the flow at showers with 2 working is approx 18-20 l/m on the middle floor of a 3 storey house the cylinder and accumulator are on the top floor
we also ran 22mm balanced supply's to showers.

hope the above is of help

Steve

 

[elbitrevnoc]

Thanks for the further thoughts Steve. I still have the twin button Quartz control, but I understand that the processor unit has been changed. at first I was still able to select either standard or boost settings, but this now defaults to the latter.

I think the supply into the house is 22mm, but I'm not sure yet how the showers themselves are connected. As I said in an earlier post, one of the three showers seems pretty good and i wonder what differences there may be in the way they are plumbed in.

The point about using an accumulator is noted and has occurred to me as well. I have to say that my heart sinks at the thought of this - I wish I'd left a tank in the roof and left the showers on pumps!

 

[elbitrevnoc]

Believe it or not, this problem is still ongoing! Latest theory is that there is deifintely some blockage in the pipework somewhere.

If it's not a stupid question, could anyone tell me how someone goes about tracing a blockage somewhere in the pipework? I guess we can (probably) narrow it down to the pipework that's been installed as part of the new system/loft-build, but i imagine this needs some sort of 'forensic plumbing' specialist! Is there some hi-tech solution for this sprt of problem - I don't like the thought of pulling up carpets and knocking holes in walls!

Thanks!

 

[njk]

Hi

I would find it very surprising if all your showers are blocked and none of your other outlets.


From your explanation, there are two things I would look at first.

1. The balanced supply. It basically means that you have the same amount of water going to the cold water supply and the hot water supply.
It is not controlled by the pressure reducing valve itself but by balanced cold water connection that is normally connected to it. It is not as complicated as it sounds, it is basically just a tee with one side going to the cold water and the other directly in to the hot water cylinder, without any draw off points (VERY IMPORTANT).

2. The height of the cylinder. If your cylinder is in the loft, you will lose pressure depending on the height, i.e. if the cylinder is 10m high, you will lose 1 bar pressure.

1) Can you find the the pressure reducing valve, it sometimes is in one part, sometimes two. It should be close to the cylinder. (I have attached a photo of it in two parts)

//media.diynot.com/70000_69207_16833_56677669_thumb.jpg

2) Do you have a pressure meter on the pipework by the cylinder, (on the reducing valve?)?
3) Do you have any photos from the loft?


So could this explain your problem?
If you have 2 bars coming in at ground level, reduced to 1 bar due to the positioning of the cylinder, unbalanced water pressure and then high pressure outlets in the showers (smaller bore in the mixer).

Hope it helps

Lolli