Called out to another Vaillant Eco-tec today in Benfleet, Essex.
The customer complaining that the heating is coming on when the hot water is being called for.
After arriving on site this morning to diagnose the problem, I found the problem to be the diverter valve.
After draining down the boiler, checking a re-charging the expansion vessel, the old faulty diverter valve was removed and the new one installed. It was then filled and tested.
Here at Calgas we are Vaillant boiler specialists. With over 10 years experience of working on Vaillant boilers, we are the company to call.
If you need any advice on your Vaillant product please feel free to call or send us an email, advice comes free and we will help as best a possible.