Most solar systems have bypass valves that leak (they are designed that way). I hate to ask, but are you SURE that these valves are fully open? If they were closed, they would still allow a little water to flow into the solar, but would create a huge pressue delta.
Or, is your 3-way actuator valve possibly getting stuck halfway open (sending only a little water through the solar but creating one heck of a bottle neck in your system)?

Reply With Quote

Bookmarks