worcester danesmore oil boiler CH function not working ....

[billy7771]

hi chaps any ideas on this one please i am stumped!
boiler runs fine on HW function no issues.
on the CH there is an issue.........
comes on fine from cold on timer
after i while ( not sure yet as to how long but the rads are hot) it goes off.
thought it was the thermostat turning it off as if it was up to room temperature but if i adjust the temp of the thermostat up it will still not come on.
the light to indicate that the CH function is on (ie in the programmed range) but the red power light is not lit.
if i try to turn the HW function on at this point the boiler fires up as normal

hope that makes enough sense for someone tt offer some help???
many thanks in advance

 

[oilman]

It's not the boiler that has a fault, it's the CH diverter valve if it's a 2 port, if it's a 3-port, it's that one.

 

[billy7771]

thanks oilman
when i got up this morning the heating was on fine?
what can be happening to the valve to make it work intermitantly .....any ideas?