fatgeezer wrote:
The water is hand hot, I have two thermostatic valves that switch on
the Hot pipe and Central heating. I turned up the thermostat that just

sits on the outside of the ho****er tank. Nothing changed. So I
replaced this thermostat.

Please clarify this. Are these two thermostatic valves, in that they
are similar to thermostatic radiator valves? Or are they electric
thermostats which operate separate motorized (2-port most likely)
valves? Any makers' names or product numbers on them?

The stored hot water won't get any hotter than the boiler water.What
setting is the boiler thermostat on?