Boiler Time Clock

[gemius]

I have a Vaillant ECOmax 828.

Recently it has been firing up during the night despite the timer being off and now it doesn't want to shut down on the timer. It just keeps trying to start up again, fails to start and keeps trying again.

I've now left it on permanently and control it from the thermostat without any problem.

Does this prove that the Time Clock is faulty? I've had a look at it and feel confident I can fit a new clock myself.

 

[Elmbeard]

Is it cold where the boiler is?

On my boiler there is a frost stat which overrides the timeclock. In order to prevent water freezing, the boiler fires up heating the water about to freeze.

How is it after the boiler has warmed up?

 

[gemius]

The boiler is in our bedroom wardrobe so I can't see it getting too cold.
It is of course on an external wall in an old house but I've had insulation blown into the cavity so it shouldn't get that cold.
That of course is only relevant to what the frost thermostat is set to.

I don't know where to look to check the thermostat. Can anyone advise me on that please.

On the second point the boiler was warm as this weather it is on all day.