For residential and commercial applications, Matco-Norca offers its Tankless Water Heater Kits consisting of separate hot and cold valves with pressure relief valve included. Hot and cold valves are available in union x threaded or union x solder ends with an integral 3/4” FNPT relief valve port. The companion 3/4" pressure relief valve is designed specifically for protection of hot water supply systems. It is installed directly on the tank or in a tee and can go on either side of the water