Vaillant 110 Timer Unit Not Turning Boiler Off at Set Times

[alig31]

Hi all,

I have just moved into a new house and having a few issues with the boiler. It is a combi and both the DHW and CH work ok in so much that the Rads get hot and HW out the taps. The problem seems to be the timer as it doesn't seem to turn the boiler off at the specified times. I have tried all pins out and in but when I turn up the thermostat the boiler always kicks into life. Has anyone got a wiring diagram of the timer unit (the mechanical aspects seem to be fine) or a method to test the timer ....or any bright suggestions.

Thanks in advance

Al

[plumbbob]

You should be aware, the timer does not directly control the boiler so it is perfectly possible for it to fire even if it is the off position.

What should happen of course, is the radiators shouldn't get hot unless the frost stat is kicking in or the boiler is exercising itself.

The 110 timer is a built in device so a wiring diagram is not available.

[alig31]

Thanks for the response. The timing unit is a plug in unit which can be removed from the boiler without any effect to the boiler save no timing, so essentially a stand alone unit.