An HVAC controller may wirelessly communicate with a mobile wireless device that provides a user interface for interacting with the HVAC controller. In some cases, the communication module wirelessly receives a sensed parameter from a remote wireless sensor in a living space of the building and receives a wired input from a return air sensor. A controller may be operatively coupled to the communication module and may control the HVAC system based at least in part on the sensed parameter from the remote wireless sensor when the sensed parameter from the remote wireless sensor is available and, in some cases, control the HVAC system based at least in part on the return air parameter when the sensed parameter from the remote wireless sensor is not available.

A heater for heating air includes an inlet, an outlet, and an air duct between the inlet and the outlet. A fan and a heating element are positioned in the air duct. A first temperature sensor is positioned at or near the inlet and configured to measure a first temperature of ambient air at the inlet. A second temperature sensor in positioned in the air duct and configured to measure a second temperature of heated air flowing through the air duct. The heater is configured to control heating power and fan speed based on measurements taken by the first and second temperature sensors.

A heater for heating air includes an inlet, an outlet, and an air duct between the inlet and the outlet. A fan and a heating element are positioned in the air duct. A first temperature sensor is positioned at or near the inlet and configured to measure a first temperature of ambient air at the inlet. A second temperature sensor in positioned in the air duct and configured to measure a second temperature of heated air flowing through the air duct. The heater is configured to control heating power and fan speed based on measurements taken by the first and second temperature sensors.

The present description discloses a combustion type water heater that heats water by burning fuel. The combustion type water heater includes: a burner that generates combustion gas by burning the fuel; a heat exchanger that exchanges heat between the water passing through on an inside of the heat exchanger and the combustion gas flowing on an outside of the heat exchanger, an exhaust pipe that discharges the combustion gas after the heat exchange in the heat exchanger as exhaust gas; an exhaust gas temperature detector that detects a temperature of the exhaust gas flowing in the exhaust pipe as an exhaust gas temperature; a clog degree detector that detects a degree of clog in the exhaust pipe; and a scale buildup determiner that determines whether or not scale has built up inside the heat exchanger based on the exhaust gas temperature and the degree of clog in the exhaust pipe.

A heat-pump circuit may include an indoor heat exchanger, an outdoor heat exchanger, a compressor adapted to circulate a working fluid between the indoor and outdoor heat exchangers, and an expansion device disposed between the indoor and outdoor heat exchangers. A monitor for the heat-pump system may include a return-air temperature sensor, a supply-air temperature sensor, and a processor. The return-air temperature sensor may be adapted to measure a first air temperature of air upstream of the indoor heat exchanger. The supply-air temperature sensor may be adapted to measure a second air temperature of air downstream of the indoor heat exchanger. The processor may be in communication with the return-air temperature sensor and the supply-air temperature sensor. The processor may be programmed to determine a working-fluid-charge condition of the heat-pump system based on the first and second air temperatures.

A method for remotely diagnosing an abnormality in a climate control device includes the following steps: (a) receiving, at a diagnostic device remote from the climate control device, a signal representing one or more operating parameters of the climate control device, (b) generating, at the diagnostic device, an operating state metric at least partially from the signal representing the one or more operating parameters, (c) comparing, at the remote diagnostic device, the operating state metric to a reference metric, and (d) diagnosing, at the remote diagnostic device, the abnormality in response to a difference between the operating state metric and the reference metric.

An apparatus and system for a combination space and water heater including a controller device and a method for control. The controller device is a self-contained system that can be added to, or in combination with, existing water heaters and hydronic air heating systems using standard plumbing connections, and provides a potable water system without any need of an intermediary heat exchanger. The controller device automatically monitors a heating capacity of the water heater and the hydronic heating coil over time, and correlates measured heating loads with one or more environmental temperatures, thermostats, user settings, and/or a supplemental heating system.

A supplemental heating system includes an enclosure that encloses a primary heating device. The enclosure includes an inlet damper, an outlet damper, and an intermediate damper. In an idle state, the inlet damper and outlet damper are open while the intermediate damper is closed. In an active state, the inlet damper and outlet damper are closed while the intermediate damper is open, so that air is circulated within the enclosure.

A flame sensor for a furnace of a heating, ventilation, and air conditioning (HVAC) system includes a sensor body and an electrically conductive member of the sensor body. The electrically conductive member is configured to be disposed within a flame region of a burner of the furnace and configured to receive electrical current from a controller of the furnace. The flame sensor also includes an anti-oxidation coating disposed on an outer surface of the electrically conductive member and configured to transmit the electrical current from the electrically conductive member. The anti-oxidation coating is configured to contact a flame produced by the burner and expose the electrical current to the flame.

A heating unit for a heating, ventilation and/or air conditioning (HVAC) system may have a first airflow path through the heating unit, a second airflow path through the heating unit, and a heater assembly having a first heating coil positioned within the first airflow path, a second heating coil positioned within the second airflow path, and a coil divider separating the first heating coil and the second heating coil.