I just installed a 1 HP, 2 speed Pentair Whisperflo.....I run it on low speed for circulation and filtering. I installed a relay onto my solar controller so that when heat is demanded , and the diverter valve directs water to the roof the pump is switched to high speed.
The problem is that it is overpressurizing the panels and has blown a couple of fittings off. Low speed isn't enough to run the panels effectively so I need to install a bypass line.
My question is where is the best place to install the bypass? I have seen drawings where they have it installed after the check valve at the filter but before the electric diverter valve...this doesn't make alot of sense to me as it would decrease the flow when the panels are off....I was thinking it should be installed after the diverter valve on the supply line to the panels so that it only bypasses in "heating mode".
I was also thinking of installing a check valve on the return line from the panels because it's "backfeeding" (pressurizing) the panels when I run the pump on high speed for vacuuming.
Any input is appreciated.