vaillant combi vcw sine 18 t3wh

[mozzie]

Hi, can anyone help me please

My vcw sine 18 boiler is cutting out before reaching normal temp, the radiators are only luke warm. The dhw is fine and at normal temp. I have drained and refilled the system and bled all radiators but still same. The temp of return pipe is only showing a max of 60° when the boiler cuts out and drops to 40° before the boiler restarts, The furthest away radiator isn't heating at all, would this stop the boiler from reaching correct temp.
Any help would be appreciated.

maurice

 

[Agile]

It sounds to me as if the wax element in what I call the diverter valve is not moving fully to the CH position.

A thermal survey inside the boiler would usually confirm the problem.

But it could be other things like temperature sensors etc.

Tony