Re-reading your original post, the problem is one set of rads getting hot when the other set is calling. A more common problem is rads getting hot when DHW calling. But if it's piped as attached sketch that could give your symptoms. From the photos posted I don't think it's possible to be sure it isn't. The fault could be remote from the boiler room.Hi,
Interleaved was mention in a question:
A) all combine into two separate pipes, before joining together in a single place and flowing into the return pipe visible, or
B) are they interleaved so some (but not all) upstairs pipes are combined with some (or all) the downstairs pipes, and the remaining upstairs pipes combine later in the run?
The answer from the plumber was B.
He suggested one way values on each radiator, but people have suggested this is a botch job. So I’ve asked him to pipe it as per A above. Hopefully this should resolve the issue. Anyone think different before they start tomorrow? Sounds silly having to ask when I have the plumber, but I’ve been messed about so much. Appreciate everyone’s input!
A schematic of the complete system would be useful, but might need a bit of investigation.