Hi.
Hoping someone can advise.
My downstairs CH system is on 3 loops.
First loop 3 rads,
Second loop 7 rads,
Third loop 3 rads.
All loops return via the main 22mm pipe to the boiler.
However, the second loop also feeds 6 upstairs rads, making a total of 13 rads on that loop. The upstairs rads...