In message , YAPH
writes
So if you run both boilers you have paralleled 15/60s pumping through a
single 15/50? Now that's weird! Have the boilers been changed from
something else in the past?

The boilers may well have been changed: the rads are non-finned types but
the boilers are Baxi Solo 2s so they're newer than the original
installation I'd guess. Even so it would be odd if they'd fitted new
boilers with extra pumps and not removed the pair of 15/50s.


Don't forget that there is an 8-10min pump overrun from each pcb


--
geoff