Boiler is live without time clock calling???

[fatfishface]

My boiler is switching on without the time clock calling for HW or CH.

I recently fitted a Honeywell wireless stat but it was working fine for about 2 weeks.

Any ideas? Could a faulty diverter valve cause this condition?

 

[Best]

Yes. The actuator (head part) usually is the culprit solely.
Sometimes the valve body can also cause the actuator to stay on if the body jams, so consider the option of replacing entire valve if body is checked first.

 

[EPH]

Check the wiring centre, if the browns life when the programmers off then its that. If the orange is live then the bro less your zone valve.