Check Valve for Solar Swimming Pool Heating Panel Systems. Controls water pressure back flow to protect your filteration system. Prevents water from rushing back on your circulation pump and possibly causing damage to your filtration system. Recommended for all Roof Mounted Solar Heating Panel Systems. Made of sturdy PVC. 5 pvc check valve is to prevent water back flow pressure when the pool pump is turned off. This will help prevent any issues with your pool pump and filter circulation system. The item “Check Valve for Solar Swimming Pool Heating Panel Systems” is in sale since Thursday, March 26, 2015. This item is in the category “Home & Garden\Yard, Garden & Outdoor Living\Pools & Spas\Pool Parts & Maintenance\Pool Heaters & Solar Panels”. The seller is “bestpoolbuys” and is located in NY. This item can be shipped to United States, to Canada.