Method and device for preventing corrosion in hot water systems

A method of controlling a real-time oxidation-reduction potential (“ORP”) in a hot water system to reduce corrosion in the hot water system, the method comprising:

• (a) defining one or more operational protective zones (“zone” or “zones”) in the hot water system;
• (b) selecting at least two of the defined zones, wherein at least two of the selected zones includes at least one ORP probe operable to measure the real-time ORP and communicate with a controller;
• (c) either intermittently or continuously measuring the real-time ORP at one or more of the selected zones while the hot water system is at operating temperature and pressure;
• (d) transmitting the measured real-time ORP to the controller;
• (e) assessing whether the measured real-time ORP or a calculated ORP based upon the measured real-time ORP conforms to an ORP setting, wherein the ORP setting is either a same ORP setting for each of the selected zones or a different ORP setting for at least two of the selected zones;
• (f) performing at least one of the following actions if the measured real-time ORP or the calculated ORP does not conform to the ORP setting:
• (i) feeding an effective amount of one or more active chemical species into the hot water system, (ii) removing an effective amount of one or more active chemical species from the hot water system, and (iii) changing a system parameter;
• and
• (g) optionally ramping from one of the selected zones to another one of the selected zones after a triggering event.