# US 8,740,101 B2 · Backup control for HVAC system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,740,101 B2 - Document ID: US8740101B2 - Status: Granted - Kind: B2 - Application number: 13/035,068 - Filed: 2011-02-25 - Published: 2011-06-09 - Granted: 2014-06-03 - Earliest claimed: 2008-07-10 - Assignees: Honeywell International Inc. - Applicants: Cary Leen; Gabriel A. Bergman; Jiri Frint; James Grenkoski - Inventors: Cary Leen; Gabriel A. Bergman; Jiri Frint; James Grenkoski - Web page: https://patentgrep.com/patent/US8740101B2 ## CPC - G05D 23/1931: {to control the temperature of one space} - F24F 11/30: for purposes related to the operation of the system, e.g. for safety or monitoring - F24F 11/38: Failure diagnosis - F24F 11/56: Remote control - F24F 11/63: Electronic processing - F24F 11/77: by controlling the speed of ventilators - F24F 11/32: Responding to malfunctions or emergencies - F24F 2110/10: Temperature - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES - F24F: AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING (removing dirt or fumes from areas where they are produced B08B15/00; vertical ducts for carrying away waste gases from buildings E04F17/02; tops for chimneys or ventilating shafts, terminals for flues F23L17/02) ## Abstract An equipment interface module that can operate one or more pieces of HVAC equipment in accordance with instructions received from a properly operating thermostat, yet can also operate the HVAC equipment when communications between the thermostat and the HVAC controller are lost due to, for example, low battery power at the thermostat, malfunctioning thermostat sensor(s), malfunctioning communication and/or thermostat circuitry, electrical interference, and the like. In some instances, the equipment interface module may regulate the HVAC equipment in accordance with a signal from a remote sensor when communication with the thermostat is lost. ## Claims ### Claim 1 An equipment interface module configured to communicate with a wireless thermostat and a temperature sensor, the equipment interface module also configured to provide instructions to an HVAC system to affect the temperature of an inside space of a building, the equipment interface module comprising: a sensor input port for receiving an output signal from a temperature sensor; a wireless receiver for receiving wireless signals from a wireless thermostat, wherein the wireless thermostat is located remotely from the equipment interface module; a controller in communication with the sensor input port and the wireless receiver, the controller programmed to determine if the equipment interface module loses communication with the wireless thermostat, and if not, provides instructions to the HVAC system in accordance with and in response to the wireless signals received from the wireless thermostat, and if so, provides instructions to the HVAC system without input from the wireless thermostat but in accordance with and in response to the output signal from the temperature sensor. ### Claim 2 (depends on 1) The equipment interface module of claim 1, wherein the temperature sensor is wired to the sensor input port of the equipment interface module. ### Claim 3 (depends on 1) The equipment interface module of claim 1, wherein the temperature sensor is a return air sensor disposed in a return air duct of the HVAC system. ### Claim 4 (depends on 1) The equipment interface module of claim 1, wherein the controller provides instructions to the HVAC system in accordance with and in response to the wireless signals received from the wireless thermostat if the equipment interface module regains communication with the wireless thermostat. ### Claim 5 (depends on 1) The equipment interface module of claim 1 further comprising a memory for storing one or more temperature set points, wherein if the equipment interface module loses communication with the wireless thermostat, the controller provides instructions to the HVAC system to maintain a temperature at the temperature sensor that is related to one of the set points. ### Claim 6 (depends on 1) The equipment interface module of claim 1, wherein the HVAC system includes a furnace that has an integrated furnace controller, and wherein the equipment interface module is mountable separate from the integrated furnace controller. ### Claim 7 (depends on 6) The equipment interface module of claim 6 further comprising one or more terminals in communication with the controller for electrically connecting the controller of the equipment interface module to the integrated furnace controller via one or more wires. ### Claim 8 (depends on 1) The equipment interface module of claim 1, wherein the HVAC system includes a furnace that has an integrated furnace controller, and wherein the equipment interface module is integrated with the integrated furnace controller. ### Claim 9 An HVAC system comprising: an HVAC component having an HVAC controller; a remotely located wireless thermostat; an equipment interface module in wireless communication with the wireless thermostat and in wired communication with the HVAC controller, the equipment interface module is configured to provide instructions to the HVAC controller in accordance with and in response to signals received from the wireless thermostat; and wherein the equipment interface module is also configured to provide instructions to the HVAC controller without input from the thermostat if the equipment interface module loses communication with the wireless thermostat. ### Claim 10 (depends on 9) The HVAC system of claim 9, further comprising a sensor that is in communication with the equipment interface module, the sensor providing the equipment interface module with a control signal related to an environmental parameter within a building. ### Claim 11 (depends on 10) The HVAC system of claim 10, wherein the sensor is wired to the equipment interface module. ### Claim 12 (depends on 10) The HVAC system of claim 10, wherein the sensor comprises a return air temperature sensor. ### Claim 13 (depends on 9) The HVAC system of claim 9, wherein the equipment interface module operates the HVAC component in accordance with a predetermined temperature setpoint after communication is lost between the equipment interface module and the wireless thermostat. ### Claim 14 A method of operating an HVAC system having an HVAC component and an HVAC controller, an equipment interface module in wired communication with the HVAC component, a wireless thermostat in wireless communication with the equipment interface module, and a sensor in communication with the equipment interface module, the method comprising: controlling the HVAC component using the equipment interface module in accordance with signals provided by the wireless thermostat; determining if transmission of valid signals between the wireless thermostat and the equipment interface module has failed; and if it is determined that transmission of valid signals between the wireless thermostat and the equipment interface module has failed, controlling the HVAC component using the equipment interface module and the sensor until it is determined that transmission of valid signals between the wireless thermostat and the equipment interface module has been reestablished. ### Claim 15 (depends on 14) The method of claim 14, wherein if it is determined that transmission of valid signals between the wireless thermostat and the equipment interface module has been reestablished, returning to controlling the HVAC component using the equipment interface module in accordance with signals provided by the wireless thermostat. ### Claim 16 (depends on 14) The method of claim 14, wherein the sensor is wired to the equipment interface module. ### Claim 17 (depends on 14) The method of claim 14, wherein controlling the HVAC component using the equipment interface module and the sensor includes: monitoring an environmental condition via the sensor; and operating the HVAC component to achieve a desire environmental condition at the sensor. ### Claim 18 (depends on 17) The method of claim 17, wherein the desired environmental condition corresponds to a predetermined set point. ### Claim 19 (depends on 18) The method of claim 18, wherein the predetermined set point is a predetermined temperature set point. ### Claim 20 (depends on 18) The method of claim 18, wherein the predetermined set point is stored in the equipment interface module.