A
Associate
It's been piped wrong. Get the installers back but on Eco you'd have more luck picking 123456 for Saturdays lottery.
Would you say it's been piped wrong by these new installers, and nothing to do with the original 30 year old installation (all radiators worked fine before new work)?
If so, for my own reference, any "ideas" (I know it's going to be vague without you inspecting in person, but even your and other members' "educated guess" would help me) what they might've done wrong?
Thank you.