The flow sensor is the on-switch for the unit. the impellar registers the rate of hot water demand greater than 0.5gpm and the heater will activate and start combustion. There is generally no error code associated with the flow sensor operation except in multi unit installations (EC410) where the potential blockage in one or more heaters can be identified
Main Water Control Valve
The main water control valve measures the inlet water temperature and controls the amount of water that will be heated up in the heat exchanger.
Bypass Water Control Valve
The bypass water control valve regulates the water temperature and volume of water leaving the heater. Located just after superheated water leaves the heat exchanger, the bypass valve mixes in cold water to reduce the temperature of super heated water and to fortify the volume and pressure losses experienced during the heating process. The valve can achieve its full range of motion in less than 5 seconds and is able to correct temperature output to within 2 degrees. The mechanics of the valve’s logic can identify when the heater needs to refire for a change in hot water demand or make the mix ratio adjustment alone to correct a temporary pressure fluctuation in the plumbing.