Adjustable thermostatic mixing valve - 95 degree to 150 degree setting range - 75 PSI maximum dynamic working pressure - 150 PSI maximum static working pressure - 195 degree maximum hot water inlet temperature - The 520 series three way thermostatic mixing valve is used in systems producing domestic hot water. It maintains the desired output temperature of the mixed water supplied at a constant set value compensating for both temperature and pressure fluctuations of the incoming hot and cold water.