[zvezdast]

I have a Mixet shower faucet (MDXTR-5). In the last several months, the cold side of the faucet has been having a very low water pressure. The hot side has a good pressure. The house is 11 years old, and I've lived there just for a year, so I don't know for sure how old the faucet is.
I found another post on this site, that suggests there may be a blockage in the faucet.
Since the shower pipes are inclosed in the wall, and there is no valve, would I need to close the watter supply to the house in order to open up the valve and pull out all the parts? I heard that putting all the parts back together into the wall may be tricky. Is this job too complex for a lay person, or is it worth calling a plumber?
Thanks

[ballengerb1]

It is never a bad idea to call a plumber but many projects can be done by a homeowner. There is most definitely a valve. First shut off your main and drain down the water by opening a faucet in a lower part of the house. Remove the faucet handle whether it is a single handle or two handles. Once the handle is removed you should see a brass nut shape valve stem. Yes you can screw up the pipes inside your wall but rarely this connection. There are several pipes and probably a mixer in the system all adding to the strength.

[iamgrowler]

This particular model should have integral stops cast into the body of the valve, just behind the large round escutcheon plate that you can turn off with a flat blade screwdriver -- You'll need to remove the volume control (the outer knob) and the temperature setting handle (the inner blade handle) You'll then need to remove the round sleeve with a crescent wrench.

The cartridge can then be removed by gripping the stem tightly with a pair of channel locks and pulling outwards.

Once you get the cartridge out, you should slowly turn each stop on, one at a time, just long enough to flush out any debris before installing the new cartridge.