I have a rooftop solar heater, not sure which brand. It was already here when I moved in a couple years ago. I noticed that during the past couple days there is water coming off my roof any time the pool pump is on. The heater is turned off, and the valve is closed. When I turn the pump off I can hear the vacuum breaker on the roof draining the panels. The filter pressure is at 10 psi with the solar heater off, it goes up to 16-17 with the heater on.
I am trying to figure out why the solar heater is being filled with water even when it is turned off. Any suggestions on where to start? Thanks