2. Protection against failures in the water supply system. The main element of this protection is the valve, in automatic mode, draining water from the hermetic tank when exceeding the internal pressure or excessive overheating. Check the work of protection somewhere a month. This is done like this — remove the control panel or unscrew the Dorot valve 300, let it light up to an insignificant amount of water, after that, return the valve to its place.