Mira Excel shower. Unable to use anything but maximum flow.

[Stonedofmoo]

Hi all

We've had a Mira Excel mixer shower fitted for about a year now. Since getting it though we've never been able to use anything but the most powerful flow setting.

If we don't the pipes either start a high pitched whine you can hear right across the house, or instead the flow starts pulsating from the shower head in fits and spurts, and you can hear the pipes feeding it crashing and banging about behind the wall, you can feel it through the floor too.

Any ideas what is up with it? It's done this literally since day 1.

Cheers

 

[kevplumb]

whats the hot water system

gravity

pumped

combi

We've had a Mira Excel mixer shower fitted for about a year now. Since getting it though we've never been able to use anything but the most powerful flow setting.

why didn't you get the installer to sort it

 

[Stonedofmoo]

Oh sorry, it's running off main pressure and it goes through a Worcester 28i RSF combi boiler.

We have very high pressure here so theres no need for power assistance. As said there is certainly no problem with maximum flow, it's taming that maximum flow that is the issue

A friend of ours fit the shower as part of a bathroom rebuild. I didn't even notice the issue at first because I always shower with maximum power.

 

[tonybhoy]

Phone Mira tech for advice specific to your set up but they will probably tell you to have a PRV installed on the mains, you might have to fit one on the hot water outlet of the boiler which I'm presuming is a combi.

Does the noise stop if you run another hot tap?

PRV= Pressure Reducing valve.

 

[Stonedofmoo]

I actually have a valve on both the hot and cold pipes that adjusts the water to the shower. My friend fitted those in case we needed to switch off the water to the shower alone.

I could use these to adjust the pressure?

Is this the issue with it then, the pressure is too high?

 

[kevplumb]

I could use these to adjust the pressure?

no

Is this the issue with it then, the pressure is too high?

sounds promising

 

[Stonedofmoo]

I don't understand. These are inline valves on the pipes that feed the shower, and only the shower and they let me adjust the flow.

Surely then I can use this to reduce the cold pressure going to the shower and create a more equal flow which will resolve the issue?

What does this PRV do differently?

Many thanks

 

[kevplumb]

they will reduce the flow they will NOT reduce the pressure

bit like turning a tap down if you stick your finger over the end its still got the pressure

 

[tonybhoy]

You only have iso valves which can only control the flow of water going through them, they can't reduce the pressure only a PRV can do that!

This is one of those common plumbing misconceptions. People think by turning down the stopcock they are controling the pressure on the house side of the valve but they ain't

Even if you reduce the water flow down to a trickle of water coming out the otherside the pressure will be exactly the same.

Flow and pressure are two completely different things.

Have you called Mira? They will want to know the static and dynamic pressure of your cold mains and also the same info re the hot supply leaving your boiler.

BTW, the guy who fitted the mixer should have checked all of this, horse bolt and door springs to mind here.

01242262888

 

[Stonedofmoo]

lol well I've learned something new today. I never would have thought of it that way.

I'll get a PRV fitted then. It won't slow down the supply of cold water round the house will it? I know where the mains water feed comes in so I'll see if I can get one fitted there.

Thanks for your help

Chris

 

[tonybhoy]

I'll get a PRV fitted then. It won't slow down the supply of cold water round the house will it?

Chris

Probably, it will ensure the entire house plumbing is kept at a constant three BAR and you can adjust the pressure up or down however I would strongly advise you to get the mains pressure checked before you go throwing money at the problem becuase you might not even have three BAR mains pressure in the first place, the problem could well be a faulty cartridge in the shower mixer which is why I keep advising that you call Mira since the valve is only a year old and is still under guarantee provided, of course, yer pal has fitted it properly.

Mira, wil however, charge you to come out if there is nothing wrong with your mixer. This mixer is probably the best mixer on the market right now and is designed to work at a max 5BAR dynamic pressure, anything above that will cause problems and may even damage the valve however unequal pressures on the hot and cold can cause the valve to make noises which is why you have to check both hot and cold supplies in the house.