Hello, Im hooking up 3 panels. 5' x 8' of evacuated tubes for my panel. There are being located on the roof of a building housing the pump, filter, etc. for an inground pool that is 35' x 14' freeform style. My question is related to the piping specifically. Will I need a vacuum breaker or a vent at the top of the panel piping on the return or supply. I am assuming i need to drain these panels when the pump is off to avoid boiling the water off , etc. I will pipe them so they can gravity drain back on the return side but just need some proven advise. I plan to add a check valve on the supply side after the pump to the panels. I dont have an automatic 3 way valve at this point, just planning on open and closing valves to panels and playing with the bypass valve for proper flow over panels. So, my biggest question is just regarding a needed vacuum breaker or vent? I live in southern ontario, canada. My pool is a salt water, fibreglass inground pool. Filter is a cartridge filter with a pentair 1hp pump. All piping is 1 1/2" pvc shed 40 pipe within the pump and filter now. Thks for any help