Only recently, when the temperature in my water cylinder (Airing cupboard) set at 60 the water in my mixed showers are perfect but the taps in the wash basins get so hot the water can scold ones hands. If I reduce the temperature, the showers get warm and we have to put the dial (red) right to the end to get fairly warm water. Can someone please help? Thank you.
It sounds like there is a problem with the thermostat. Try turning the unit off or unplugging it for ten seconds and plugging it back in. If it is still doing the same thing, then it could be a bad thermostat.
Given that the regulation of the water temperature is subject two two key factors, the most likely culprit is the thermostat. Now, one should never eliminate a mechanical problem as the possible cause, but again, what you have described follows the pattern of an intermittent temperature change. And that sound electrical. If after powering down, the thermostat fails to operate properly or at least temperatures for your water comes back into fold, then it may be necessary to purchase a new thermostat. Given some of the uncertainty around this issue, it may be prudent to call upon a plumber to help you with both the diagnostic analysis of what is really going on and if a new thermostat is needed, then it would serve in your best interest to ensure that it is the correct type and is properly installed.