The control knob on my Mira 722 is leaking how can i fix it

Suzy, December 2008

Just serviced my 1981 Mira 722 - now I need to know how to regulate it and set the lever position.
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I also need to know which side the hot & cold supplies go to

Ray brinkman, September 2013

Actually it is a high pressure sytem, frequently running off an eletric in line pump.

Spares availability good but shop around.

Always seizes in hard water areas - regularly. Easy to work on. If in doubt Mira will send diagram.

Plastic bush strips in control lever - you can turn this around to extend its life but you will need a new one eventually!

Mine seizes now so often I probably need complete new innards.

To unseize...strip (the unit too), de-scale until the brass is a light, clean colour with no deposits. When you look at it it looks fine but after a descale/clean it will operate 100% better.

Perhaps an expert plumber can advise whether a water proof lubricant should/can be appled to the workings to stop it seizing.

tinonline, August 2011

The 722 has a seal on the shaft that goes through the casing, this seal has hardened and is leaking water-clean the area with scotchbright-replace the seal and put back together, seals available from mira or buy a set of o rings from screwfix-good mixer-runs for ever, the only fault is it seizes from residue in soft water-or is that hard water-I forget- areas

chris, March 2009

Pat, i had look on the Mira website but could not find the information you talk about. can you provide a link for this? thanks

Toby, January 2009

Suzi , The 722 is a very old Thermostatic mixing valve and was made for low pressure systems. Have you had any recent alterations to your heating system that would raise that pressure possibly resulting in water passing the low pressure seals ? Parts are still available from Mira. Maybe its just getting old ?

Alan, December 2008

Contact the company directly speak to customer services and tell them you need a service kit for your particular shower. Give them as much detail as you can as there are many different types of shower unit made by this company.

The removal and replacement of the parts can be done by a competent person... Just ensure the electricity is isolated and the fuse to the shower has been removed, Turn off the water supply to the shower and place the shower head in the bath or shower tray and allow it to drain with the shower water control turned on. Once done remove the head and hose from the shower casing.. If you feel the job is beyond your skills call in a professional and get it done by them.....

You can find the instructions for installing the service kit on the mira web site. It is a great site and will cover many shower units.

Pat, December 2008