I have a new condensing boiler with pump and mid position valve feeding both hot water and central heating. The hot water feeds the hot water cylinder. The electronic control system does what is intended as far as I can see but heat gets from the cylinder to the radiators when the mid position valve is in the mid position even when the room thermostat is set below room temperature. This happens at any time when the ch is timed to come on, because I understand, it is meant to do that.
The system will never let us get too cold but more often than not makes us too hot.
What can be done to control the temperature entirely based on the room thermostat please.
Sounds to me as if the valve is stuck in the mid position, and sending the water into both systems.
You could test by having both the heating and water on, get someone to turn the roomstat down, while you listenen to the valve. you should hear it change position.
If not that then the roomstat could be incorrectly wired, after the boiler change. the fact that it is condensing should not make any difference.
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!