Description1/2″ non return valves are designed to combat the reversal of glycol fluids siphoning back around the pipe work to the collectors during the evening. This spring valve for solar water systems can help stop thermal heat from being lost. Also available in 3/4″ BSP. Click here for details Spring non return valve solar thermal circuit non return valve For these work in vertical position, so can be mounted to in line installations easily. Spring non return valves for solar thermal hot water systems stop heat circulating after sun set to avoid loss of temperature
