A method of determining presence of a flame in a furnace of a heating, ventilation, and air conditioning (HVAC) system. The method comprises determining, using a controller, whether a processor signal (G) is active, responsive to a determination that the processor signal (G) is active, determining, using the controller prior to assertion of a flame-test input control signal, an output state of a first comparator, responsive to a determination that the output state of the first comparator is high, determining, using the controller prior to assertion of the flame-test input control signal, an output state of a second comparator, and responsive to a determination that the output state of the second comparator is low, transmitting, using the controller, a notification that a flame is present.

A method of defrosting a heat pump device including a water tank, a heat exchanger, an electrical heating element, an evaporator, a fan for the evaporator, and a control unit. In a first operating mode, the heat pump device is controlled to heat water inside the water tank. In a second operating mode, the electrical heating element is manually activated to additionally heat the water inside the water tank. In a third operating mode, the electrical heating element is automatically activating to heat the water in the storage tank if: the power supplied by the heat pump device to heat the water inside the water tank is not sufficient; if a time limit after activation of a deicing operation has lapsed; and/or if the number of times the deicing operation has been activated during a predetermined time interval exceeds a threshold value.

An apparatus includes a high-pressure tank, a controller, a valve, controlled by the controller, and a heater.

A furnace for a heating, ventilation, and air conditioning (HVAC) system includes a fuel valve configured to regulate an amount of fuel supplied to a burner of the furnace, a draft inducer blower configured to draw an air flow into the burner, and a controller configured to determine a target operating parameter value of the furnace, determine an air to fuel ratio corresponding to the target operating parameter value, and control operation of the fuel valve, the draft inducer blower, or both based on the air to fuel ratio.

A furnace for a heating, ventilation, and air conditioning (HVAC) system includes a fuel valve configured to regulate an amount of fuel supplied to a burner of the furnace, a draft inducer blower configured to draw an air flow into the burner, and a controller configured to determine a target operating parameter value of the furnace, determine an air to fuel ratio corresponding to the target operating parameter value, and control operation of the fuel valve, the draft inducer blower, or both based on the air to fuel ratio.

In an electric water heater having adjustable set point and differential temperatures, upper and lower heating elements, and associated temperature sensors respectively operative to sense upper and lower tank water temperatures, a specially designed control system is provided for controlling the heating elements. The control system is operative to prevent dry firing of the heating elements by measuring temperatures over time with the temperature sensors.

A fluid discharge event detection apparatus measures a change in capacitance to detect the presence of a fluid in a sensing conduit where the presence of fluid indicates a discharge event. The apparatus includes a first conduit, the sensing conduit and a control valve, coupled between the first conduit and the sensing conduit. The control valve is configured to activate and fluidly couple the first conduit and the sensing conduit to one another when the control valve detects at least one predetermined condition of a fluid within the first conduit. A sensor, configured to measure a capacitance value, is disposed about the sensing conduit. A controller, coupled to the sensor, is configured to detect a change in the sensing conduit capacitance value and assert an alarm condition upon detection of the change in the sensing conduit capacitance value.

Disclosed is a system and method for monitoring hot water supply in a load control network, and more particularly for ensuring that there is sufficient hot water available for a customer participating in a demand response program that uses, at least in part, water heaters as a component of the demand response program. A multi-meter that is external to the water heater is used to monitor an electrical power supply circuit on the water heater, to report preferably volts, amps, and power factor of the water heater. The multi-meter may use these measured values to, in turn, determine a current charge state of the water heater and thus ensure maintenance of an adequate supply of hot water, even in times of demand response curtailment.

The disclosed technology includes an on-demand water heater which uses an electric heat source to heat the water. The on-demand water heater can have a low fluid capacity heating chamber which has an inlet and an outlet, an electric heat source for heating the water, and a controller to control the electric heat source and maintain the temperature of the water at a predetermined temperature setting. The on-demand water heater can be powered by a direct current power source. The on-demand water heater can also utilize a solar thermal system to provide additional heat to the water.

A tank water heater assembly is provided including a tank water heater and a drain pan provided with a sensor holder for mounting a sensor. The sensor holder accommodates a leak detection sensor at predefined distance above an inner surface of a bottom wall of the drain pan. In this way the presence of harmless small amounts of water in the drain pan do not trigger an alarm. A transport assembly is presented for facilitating transportation of the tank water heater assembly to an installation site and subsequent installation. Finally, a method for installation of a tank water heater assembly is provided.