Vaillant TW3 boiler keeps coming on and off by itself

[malachy1954]

I have an old Vaillant boiler CW 25 T3, which keeps coming on and off of its own accord can any one help with this problem

 

[weareleeds]

Is dhw pre heat switched on

 

[malachy1954]

I am not sure as the boiler is located 200 miles from where i am at the moment. If the switch is on would this be the cause and if so how often does the boiler fire up in this position.

thanks

Mal

 

[ChrisR]

ABout hourly iirc.

 

[malachy1954]

Thanks for the help.

regards

Mal

 

[Agile]

Hourly at this time fo year increasing to every 15 min during cold weather if the heating is off and its external ambient inside.