T
tamz
i have been to jobs when people have adjusted wires to suit themselves, sometimes it even works! problem is for the person following, best to keep as close to the design as possible
That is why you should learn what switches what and not depend on the standard wiring diagrams.
There are many ways to wire a heating system depending on who does it. Heating systems on new build where it is wired by the site electrician will definetly not follow a std diagram. You will open a joint box to find a pile of three cores. Easy enough to trace if you know what to look for.
The combi and unvented is not a normal thing you will come across often but they are fitted depending on the layout of the house.