The altitude control valve can control the high water level in reservoirs. Without the need for floats or other devices. It remains fully open until the shut-off level is reached. This altitude valve is designed for one-way flow only. The water tank altitude valve is hydraulically operated and pilot controlled. The pilot control operates on the differential in forces between a spring load and the water level in the reservoir. The desired high water level is set by adjusting the spring force.The pilot control measures the reservoir head through a customer supplied sensing line connected directly to the reservoir. SHSUOTE wholesale high quality altitude control valve with the best price. If you are looking for altitude valves for water tanks, Contact us now!