Worcester 240 BF/OF Scalding hot water

[campus]

Hi Everyone

Worcester 240 BF/OF Combi

Whatever the position of the temperature dial there is always scalding hot water from the tap after a short while

A short time after closing the hot water tap the pump starts and the radiators get quite hot dispersing the excess heat
The boiler does not fire up again when the pump comes on

Any idea what is amiss
Help appreciated

 

[stevetheplumber]

Hi Everyone

Worcester 240 BF/OF Combi

Whatever the position of the temperature dial there is always scalding hot water from the tap after a short while

A short time after closing the hot water tap the pump starts and the radiators get quite hot dispersing the excess heat
The boiler does not fire up again when the pump comes on

Any idea what is amiss
Help appreciated

dhw stat i would think

 

[REDSAW]

diverter valve stuck in open

 

[campus]

Gents
Thanks for your helpful replies
Do I understand correctly that the variable thermostat on the control panel is for the CH temperature and the Domestic hot water temp is controlled by a fixed internal stat

Campus

 

[REDSAW]

not sure on that particular combi but if its less than 3 years old=yes they are bosch fixed out put to 55c i think.

 

[Puddle]

The trouble with this boiler is that it works with poor flow rate,which is good but it does need setting up correctly on the hot water side,this has to be done by a competant engineer who can adjust as required to suit flow rate,as stated thermostates can be out of calibration but this has to be check by a engineer who knows the boiler