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.

An inspection execution method is performed by a computer to cause each of a plurality of apparatuses to execute a plurality of inspections. The inspection execution method includes determining an inspection schedule including at least order of the plurality of inspections, and causing the apparatuses to execute the inspections based on the determined inspection schedule.

Disclosed systems and methods relate to a water heater sensor for detecting a corrosion of an anode rod. According to embodiments, a system can include the anode rod in contact with water in a water heater, where the anode rod includes a corrodible sheath having a cavity. The system can include two electrical wires, where first ends of the two electrical wires, disposed within the cavity, are configured to come in contact with the water when the corrodible sheath of the anode rod corrodes to a certain point. The system can include a controller coupled to second ends of the two electrical wires, where the controller can detect whether the water is in contact with the first ends of the two electrical wires. The system can include an indicator to provide an indication when the water is in contact with the first ends of the two electrical wires.

A diagnostic method of a system having at least one device under test and at least one peripheral device, the diagnostic method including obtaining a response of a test action conducted on the at least one device under test; and obtaining a response of a test action conducted on the at least one peripheral device; wherein if both the response of the test action conducted on the at least one device under test deviates from an expected result based on the test action conducted on the at least one device under test and the response of the test action conducted on the at least one peripheral device deviates from an expected result based on the test action conducted on the at least one peripheral device, a cross-wire fault is raised.

A diagnostic method of a system having at least one device under test and at least one peripheral device, the diagnostic method including obtaining a response of a test action conducted on the at least one device under test; and obtaining a response of a test action conducted on the at least one peripheral device; wherein if both the response of the test action conducted on the at least one device under test deviates from an expected result based on the test action conducted on the at least one device under test and the response of the test action conducted on the at least one peripheral device deviates from an expected result based on the test action conducted on the at least one peripheral device, a cross-wire fault is raised.

Disclosed systems and methods relate to a water heater sensor for detecting a corrosion of an anode rod. According to embodiments, a system can include the anode rod in contact with water in a water heater, where the anode rod includes a corrodible sheath having a cavity. The system can include two electrical wires, where first ends of the two electrical wires, disposed within the cavity, are configured to come in contact with the water when the corrodible sheath of the anode rod corrodes to a certain point. The system can include a controller coupled to second ends of the two electrical wires, where the controller can detect whether the water is in contact with the first ends of the two electrical wires. The system can include an indicator to provide an indication when the water is in contact with the first ends of the two electrical wires.

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.

A diagnostic method for verifying the proper functioning of a fluid flow control device of a fluid system, the method including determining whether at least one pressure sensor is functional and if the at least one pressure sensor is considered functional, determining whether a bypass valve is functional and if the bypass valve is considered functional, determining whether at least one flow sensor is functional, if the at least one flow sensor is considered dysfunctional, a flow sensor fault is raised; and otherwise if the at least one pressure sensor is considered dysfunctional, using the at least one flow sensor to determine whether the bypass valve is functional, if the bypass valve is considered functional, determining whether at least one pump is functional, a pump alert is raised if the at least one pump is considered dysfunctional.

A diagnostic method for verifying the proper functioning of a fluid flow control device of a fluid system, the method including determining whether at least one pressure sensor is functional and if the at least one pressure sensor is considered functional, determining whether a bypass valve is functional and if the bypass valve is considered functional, determining whether at least one flow sensor is functional, if the at least one flow sensor is considered dysfunctional, a flow sensor fault is raised; and otherwise if the at least one pressure sensor is considered dysfunctional, using the at least one flow sensor to determine whether the bypass valve is functional, if the bypass valve is considered functional, determining whether at least one pump is functional, a pump alert is raised if the at least one pump is considered dysfunctional.

An operating method for an electric heater may include heating a fluid passing the electric heater to an outlet temperature by at least one heating element and operating the electric heater in one of a normal mode or a protection mode. In the normal mode, the at least one heating element may be supplied with at least one of a direct current and a direct voltage. In the protection mode, electrical power supplied to the at least one heating element may be regulated by pulse width modulation. The electric heater may be operated in the normal mode if a reference temperature is less than or equal to a critical temperature and in the protection mode if the reference temperature is greater than the critical temperature.