Volkera - left two pipes are return and flow, respectively.
Baxi: leftmost pipe is flow, rightmost pipe is return.
WRONG.
Yes, this seems to my conclusion too. Here’s my logic:
The left most pipe in the Baxi 430 Combi right now is the CH Flow, both from the product documentation and simple physical check - when it starts up that pipe gets hot first.
That leftmost pipe was also the leftmost pipe when the Volkera was in use, easily seen in the foto..
But from Volkera Compact 24 documentation that looks like it was the Return.
So despite my scepticism , it looks like the Baxi installer DID mix up flow/return. And it was connected “correctly” for the 15+ years before, with the Volkera, meaning the flow at the radiator end was at the TRV (top left) on all the radiators where the TRV is at top and lock shield connection at bottom. Which is all bar one of them. The exception is the radiator that works well, both connections are at bottom.
And the Gas Safe inspector didn’t notice, because he didn’t consider the radiators at all, just didn’t check flow/return.
That logic make sense?
Given the Gas Safe report from original Baxi installation, which rather soured the relationship, I don’t really know how to best proceed.
The guy I was recommended by local plumbers merchant insists that flow/return wrong way round is a non issue. My understanding is he’s plain wrong on that. Maybe he’s misunderstood my explanation? But he’s seem same images as shared here. Is that enough to just “walk away”, and find someone else ? If so, should I just tell the someone else I want flow/return swapped around, and not do what I’ve been doing which is describe the problem I am seeing ?