Worcester heatslave 1..Boiler not firing for hot water.

[logskystevens]

Can anyone help…my Worcester heatslave oil boiler does not fire up when calling for hw and the hw thermostat is unresponsive, when I had the heating on last nite I noticed the rads were pinging hot even though the heating thermostat is not set to full power, it has been locking out a few times leading up to this so something has obviously gone…any ideas?

 

[oilhead]

Diverter valve?

 

[logskystevens]

the diverter valve does stick occasionally but is moving freely from Hw to heating, could that still be the problem, it was replaced a couple of years ago?