Boiler sticking on

[JF77]

I have a standard set up central heating. Just recently the boiling is staying on even though there is no call from the controller or the room stat.
Which should i replace or is it something else?

Thanks,
Julian.

 

[45yearsagasman]

What do you mean by a standard set up? If you have motorised valves then look there for a fault. I can't be more specific, because you give so little information about your system.

 

[kevplumb]

is the boiler white by any chance ??

 

[JF77]

The system does have a motorised valve which i replaced earlier this year so i didnt think it would be that. I will check it!
.......and yes it is white!

 

[kevplumb]

did you replace the actuator as well or just the valve ?

i would start with checking the wiring

 

[JF77]

Replaced both. I will check it.
Ta

 

[JF77]

OK, the heating stuck on again last night. Turned the boiler off and let the pump over run.
Then I turned the hot water on and the 3 way valve moved to the bottom and the boiler fired up left this until it tank stat clicked off.
Then turned the heating and the valve moved to the bottom and the boiler fire up. turned the thermostat down and the boiler shut down.
so now I confused!
All the threads seem to piont to the 3 way valve sticking but I know its not and even if it is how does the 3 way valve control the boiler? surely the controller is the only device that can cpower the boiler?
Also when it's stuck on the thermostat has no click.

Ps I only replaced the actuator (Drayton 3way mid position) not the valve.

Thanks,
Julian