A system and method of operating a water heater controller that includes a powered vent electronic control circuit including a controller configured to control an operation of heating device having a powered draft inducer, a gas valve assembly configured to control a flow of a fuel gas to a burner of a heating device, and a switch assembly including a switch in each leg of a plurality of legs of a power supply to the gas valve assembly, the switch assembly configured to supply power and a return to the gas valve assembly in a first position and to open the plurality of legs of the power supply to the gas valve assembly in a second position, the switch assembly configured to indicate a position of the switch assembly to the controller.

An air-conditioning apparatus includes: a heat-source-side device that heats or cools a heat medium; a pump that sucks and transfers the heat medium; use-side heat exchangers; a heat medium circuit; flow rate control devices; indoor-side pressure sensors; a pump inlet-side pressure sensor and/or a pump outlet-side pressure sensor; a flow rate detection device that detects a pump flow rate; and a controller that performs a first operation in which the flow rate control devices are individually opened or closed and data regarding a flow passage resistance at a path related to each of the heat exchangers is obtained, and a second operation in which heat is supplied to indoor air, and calculates calculate flow rates of the heat medium that flows through the heat exchangers in the second operation, from pump flow rates and pressures detected by the pressure sensors in the first and second operations.

A device that includes a pressure sensor that adds dynamic pressure sensing capability to a furnace. In some examples the device may include a relay and other circuitry to replace the single-setpoint pressure switch used to sense the operation of an inducer fan. The pressure sensor may measure the pressure from the inducer fan and send a signal to the other circuitry, such as a microcontroller. The other circuitry may determine when the pressure from the inducer fan reaches a predetermined threshold and allow the main gas valve of the furnace to open. The other circuitry may be configured to set the pressure sensor to a variety of predetermined pressure thresholds, and thereby replace multiple pressure switches. In some examples, the other circuitry may record pressure values received from the pressure sensor over time and provide performance data, as well as other signals or indicators.

A residential and commercial hot water and steam boiler safety system and device that includes at least one hollow pipe, with one plugged or sealed end and a fitting on the other end for connecting the pipe in a substantially vertical mounting position, and at least one two float switch disposed in the pipe and electrically connected in series with a limit switch in the boiler, where the pipe is adopted for the flow and accumulation of water, so that float switch activates as the pipe fills with water and shuts off the boiler by turning off the gas valve, promoting safer boiler and steam boiler operation. Additional float switches positioned above or below in the hollow pipe may provide additional functions, such as a warning light and sound to the owner, or a notification via a telephone or cell phone system or through the home network or Wi-Fi system.

The present invention improves the user-friendliness of a hot-water supply apparatus when using hot water supply and air conditioning. A switching control unit 27, which switches between heat medium flow paths 4 and 5 according to an air conditioning ready state or a hot-water supply ready state, switches a heat medium flow path to the hot-water supply ready state by a switching valve 21 in the case where air conditioning is not used by the time an air conditioning standby time elapses during standby in the air conditioning ready state.

Disclosed herein is a water heating system including a water heater having a tank, and a first temperature sensor disposed toward a top end of the tank to measure a first temperature and a second temperature sensor disposed toward a bottom end of the tank to measure a second temperature. The water heating system can further include a controller communicably coupled to the first temperature sensor and the second temperature sensor, where the controller determines an amount of heated water in the tank based on one or more algorithms and measurements made by the first and second temperature sensors.

When a heating operation mode using a heating unit is specified and when a hot water supply request using the hot water in a hot water storage tank does not occur, an air conditioning apparatus transmits a first selection signal for selecting the heating unit to a three-way valve. When the heating operation mode is specified and when the hot water supply request occurs, the air conditioning apparatus transmits, to the three-way valve, a second selection signal for changing a destination of circulation of secondary refrigerant from the heating unit to a coil heat exchanger, and transmits an operation start signal to a refrigerant indoor unit.

A high turndown furnace for an air handling system. In one example, the furnace includes a plurality of tubes divisible by four with a first modulating valve supplying gas to ¼ of the tubes and a second modulating valve supplying gas to ¾ of the tubes. In one aspect, the furnace is capable of providing a 16:1 turndown. In one aspect, the furnace is capable of providing seamless turndown operation throughout the entire firing range.

In an aspect, an HVAC system includes an inducer motor to provide combustion airflow, and a pressure sensor to measure an output airflow pressure of the inducer motor. The HVAC system may initiate the inducer motor, and receive a pulse width modulation (PWM) signal from the inducer motor, wherein the PWM signal indicates a PWM signal of the inducer motor corresponding to a predetermined airflow pressure of the inducer motor and measured by the pressure sensor. The HVAC system may compare the PWM signal to a baseline value, and control the inducer motor based on the comparing of the PWM signal to the baseline value. The HVAC system may also generate a status notification of the combustion airflow of the HVAC system in response to the comparing the PWM signal to the baseline value.

Setting and maintaining proper pre-charge air pressure in a diaphragm or bladder-type expansion tank of any fluid system is essential for safe and efficient operation of that system. In usual practice, pre-charge air pressure checks are done by emptying the system of fluid and connecting an analog air gauge to the air input of the expansion tank. In this invention a pressure sensor that is permanently coupled to the fluid volume of the expansion tank is used to also evaluate the pre-charge air pressure in the tank. By employing a single sensor for both fluid and pre-charge air pressure evaluation, the problem of inconsistent calibration between fluid sensing and air pre-charge measuring devices is eliminated. Using the same permanently installed sensor for every test or adjustment in a given system eliminates the problem of variations in calibration between different sensors or gauges used at different testing times.