On Tue, 01 Mar 2005 15:52:31 GMT, Lobster
wrote:

We have two identical bar mixer shower valves (similar to the following:
http://www.screwfix.com/app/sfd/cat/...81667&id=21764)
in which the thermostats both recently seem to have stopped working
properly. Both about 4 yrs old, came from Screwfix originally.

In one shower, the temperature seems balanced on a knife-edge; you now
only have to touch the control to send the temp up or down by a large
amount. Although it does at least stay stable once you've managed to get
it to a comfortable temperature.

In the second one, you have to over-ride the safety button (which is a
simple feature set at an indicated 38 deg C, to stop the user from
accidentally cranking up the temp to a dangerously high level without
realising). It needs to be turned right up almost to max (an indicated
45-50 deg C) regardless of actual incoming HW temp. Again, it does
appear stable once it's working.

What can go wrong with a simple stat like this to cause these
(different) symptoms? Can they be repaired/replaced without changing
the whole shower valve? Haven't tried dismantling them yet so don't
know what's inside them...

Thanks
David