This heater has never worked correctly. The only time that it does work, is if the hot water is turned on 100%. Any time that the cold water is turned on slightly, the heater turns off. The heater leaked from the mixing valve when it was originally installed. I tightened the screw that it was leaking from, and found out that it seemed like an adjustment, so I backed it out the number of turns that it took to tighten it. Maybe this is the problem??? The box says to contact Marey for support, but there is no return communication. It has been several months that I've been trying to find out what to do.