Abstract: A supplemental heating system for heating a first fluid such as potable water. The supplemental heating system is configured for use in a recreational vehicle having a primary heating system that also heats the first fluid. The supplemental heating system includes a heating element that heats a second fluid and a heat exchanging component removably fitted into the recreational vehicle and having a first fluid conduit for permitting the first fluid to enter and exit the heat exchanging component, and a second fluid conduit for permitting the second fluid to enter and exit the heat exchanging component. Heat from the second fluid is transferred to the first fluid within the heat exchanging component and thereby provides a heating operation of the first fluid independent of the heating system of the recreational vehicle.

Abstract: A water heating system uses a heated fluid storage tank to deliver a continuous supply of water heated to a desired temperature, such as between 100°-130° F. The system also includes a furnace with altitude-sensitive control circuitry to provide multiple sources of heat for the heating system in the most effective way given the altitude at which the system is located. The system also includes a micro-controller that adjusts certain system components in response to changes in atmospheric pressure conditions that are measured by an atmospheric-pressure sensor component. There is also an automatic-air-bleeder subsystem with an optical or ultrasonic sensor mounted adjacent a suitable air accumulator. Also included is an air-release solenoid and a fuel return line.