In article , alan_m
writes
On 08/11/2017 15:31, fred wrote:
Hot water, as heated by the central heating is ferociously hot, There
is some type of adjustable wired thermostat clipped on to one of the
pipes entering the hot water cylinder but fiddling with this has no
effect.
Is this a job for a plumber or an electrician ?



Are you sure that you haven't left an electric immersion heater on
(assuming both methods available for heating a tank of water)?

The thermostat controlling the hot water in a tank is usually clipped
around the tank to monitor the temperature of the water in the tank. It
makes no sense to have it fitted to the pipes. An inlet pipe would
supply cold water, and outlet pipe would only be hot if the hot water
was being used, the boiler pipes would be supply hot water at maybe a
much higher temperature until the water in the tank reaches a certain
temperature.

Sounds like either the thermostat is u/s or set high or the valve is not
closing when the thermostat signals enough. So the water rises to the
same temperature as that coming from the boiler.
--
bert