You understand correctly, I will take some photos tomorrow and get them posted.
I am not sure how long the issue has been going on as we only moved into the property in August and only just turned the heating on in the last couple of weeks and found the problem straight away.
This is my first post here so apologies if it is in the wrong section.
I have recently moved into a new house (new for me, house was build at the end of the 50's).
I have an issue with my heating/programmer/boiler.
If the programmer is only calling for heat then the boiler runs fine...