Ok, so i'm running two reds pro pumps, and a pair of Rayvern standards.
The rV pumps are perfect, no problems and balance quite well if I do say so myself.
I've got a niggling problem with the to reds though - one is running a higher pressure than the other, and then locks up - the othr pump runs a tad lower, but then starts whining ( as "normal").
So i'm wondering if it's a head mismatch, or an internal recirculation valve buried in the block ? I can't see anything obvious - so i guess it could be inside behind the head assy?
