vrt350f

Our thermostat has a desired temperature of 20 degrees Celsius but it is turning on the heating, not matter what the temperature is. It is currently reading 26 degrees Celsius. We have tried turning the heating mode off but the thermostat turns back to auto immediately and resets the date as...

Hi all, newbie here. Less than a year ago I had a new Vaillant Ecotec boiler installed with a VFT350F controller. It connects via a VR65 control box to my existing honeywell gravity fed cylinder. It works well when programmed to come on, but I have never been able to get the 'cylinder boost'...