hello: on the wall you have 2 pipes the one that has water is the cold water the pipe without water is the hot water, hang the thermos and to the right seen from the front the cold water inlet is connected q is the pipe that has water in the wall and to the left the hot water outlet it is important that you purge the thermos well before turning it on, leave a hot water tap open and open the stopcock so that the thermos is filled when air stops stopping and observe that the jet of water is continuous just at that time close the tap and turn on the appliance to start heating when the thermostat is cut just use hot water any questions comment greetings