Problem with recently installed Mira concealed shower mixer.

[surv1v0r]

I recently had a bathroom refurbished. This included the replacement of a shower cubicle, a Mira concealed shower mixer and a hot & cold water pump. Following this work, there is a fairly dramatic leak into the ceiling void of the room below the bathroom whenever anyone takes a shower.

There is only a leak when the shower is in use. By using a 1.75m long hose and running the shower with the water going into the hand-basin I have eliminated the cause being due to cracks in the shower base or bad sealing around the shower walls. Nor is the leak is coming from the pump or any of the visible pipework.

My only remaining explanation is that there is a leak either from the shower mixer itself or from the associated pipework. The mixer and the pipework is embedded in a wall covered by tiles.

Can anyone suggest what the problem might be and how I go about investigating it further. In particular, can anyone tell me how to go about removing the outlet connector where it comes through the wall - is it an irreversible push-fit or does it screw on? Likewise, how far can I go interms of exposing the actual mixer valve?

Many thanks for any help you can give me.

Incidentally, the plumber / builder who did the work has had a bereavement and is no help at all at the moment, that will be a problem for a later date.

 

[Plumbstar Tom]

Can you post a few pictures and confirm the model of the shower

Good work on eliminating the sealing of the shower tray!

 

[surv1v0r]

Can you post a few pictures and confirm the model of the shower

Good work on eliminating the sealing of the shower tray!

Sorry, should have done this earlier. I don't know the version of the mixer but here are a couple of photos - hope they help. As you will see, I have started to dismantle the mixer but do not want to attempt more without knowing what I am doing.

 

[Radioman]

Providing the installation was done correctly The large diameter shrewd around the valve body should slide forward and off the valve. Some installers stick it to the tile with a bead of silicone. If this is the case you will need to push a very thin blade behind the plate to cut through the sealant.

Once off you should be able to see the inlets and outlet, again providing the instal was done according to MII. There should be 2 inlets and 2 outlets, 1 outlet being blocked off.


The outlet is normally a push fit over 15 mm copper pipe. The outlet has an internal o ring. Not unusual for that ring to get dislodged or split if a pipe slice has not been used on the copper.

If no obvious sign of leaks then your next and only action will be to remove tiles and plaster to inspect the pipe work. I am assuming that it is not a stud wall.

How long ago was the installation? There seems to be a lot of limescale on the chrome? Also is the hose and head original or a replacement? The incorrect sizes can cause backpressure that can blow the seals in the cartridge causing leaks.

 

[surv1v0r]

Thanks for that.

With the aid of a long kitchen knife (my wife was out shopping) I have now managed to release the surround. Unfortunately, the hole in the tile was made very precisely (by me) and there isn't much chance to see behind it so removing one or two tiles is likely to be unavoidable - and foolishly I didn't think to keep spares.

I have a feeling that plastic pipe rather than copper was used although I don't know what was used behind the tile, I had assumed that from the mixer to the outlet would be entirely Mira hardware. Should I be able simply to pull the outlet off whatever it is connected to after undoing the four screws?

As to the limescale, it is a major irritation here! A new kettle will fur up within a week but that too is another story.

The hose I am currently using was a temporary fix to try and eliminate the possibility of leaks from the base or behind the shower walls. I believe that the head and original hose are both part of the Mira kit but you may well have a point there.

 

[Plumbstar Tom]

unlikely to be Mira components for the mixer to outlet, it will be made by the plumber as the length and position is different every time. your fault could be anywhere along there.

I think tiles will need to be removed or access from the room behind has been done before when possible

 

[surv1v0r]

There is a chrome surround which would probably allow a better view if it could be removed. It appears to be loose(ish) but I don't want to force it off. Should it just pull off or would I need to dismantle the cartridge first? (I replaced a cartridge many years ago).



Access from the room behind (airing cupboard) would probably do even more damage than removing the tiles and if I found something wrong I would probably have to remove the tiles anyhow. The wall is made of Celcon blocks.

 

[surv1v0r]

I have just been having a closer look at the shower mixer and on the Internet. I have come to realise that it is almost certainly NOT from Mira, I believe that it is in fact an Aqualisa Aquavalve 609 shower mixer although I don't see why that would explain the problem I have been having?

There is a lot of limescale on the shower head nozzles (which I have just cleaned) but the problem occurred more or less from day one.

 

[Plumbstar Tom]

looking at the instructions the hole in the wall is wrong, it should have been 130mm diameter:

If installing the product built in to a solid wall, chase out a suitable recess
in the wall to receive the valve and pipe work. If installing the valve in a concealed panel mounted situation, in most cases it will be necessary to first install a suitable sound fixing in the cavity area before fixing the valve. A hole of Ø130mm is required to install the valve and gain access to inlet and outlet connectors.

http://www.aqualisa.co.uk/Aqualisa/...avalve-609-Thermo-Web-inst-guide.pdf?ext=.pdf

 

[surv1v0r]

Do you mean the hole behind the tile or the hole in the tile?

Certainly it would be impossible to "gain access to inlet and outlet connectors" through the hole in the tile. The mixer appears to be securely fastened to a cut-out in the Celcon block. I would imagine that the connections would have been tightened up and tested before the tiles were put on the wall.