Heating opratates without programmer

[mark333]

Hi
I have a Glow-worm fuelsaver conventional boiler and heating system comprising of 2 spring return valves 1 wall stat a cylinder stat ,6 rads and a programmer.
All worked fine until last week when i noticed the heating was on during what should have been the off period.
I changed the programmer.it made no difference
The wall thermosat or the cylinder stat will not turn the boiler off.

The only thing that will turn it off are the mains power or the boiler temp stat.
Has any body any ideas on this
Cheers
mark

 

[ollski]

Yep the actuator on the heating zove valve is sticking and needs replacing.

 

[mark333]

BiG Thanks Ollski
I will change the valve asap
Mark

 

[ollski]

If you want to confirm it Mark you can swap the actuators over.