Carrier Corporation

Kevin D Thompson

Daniel J Dempsey

Gary W Ballard

Dwight H Heberer

Hall Virgil

Robert W Peitz, Jr

Eric W Adams

Kent Kuffner

Duane D Garloch

William F Van Ostrand

William J Roy

Matthew Kujawa

Robert M Mamot

Paul B Kiningham

Timothy A Neeley

Christopher M Clay

Dave Tumbusch

Gary O Homme

Devin J Danielson

Andrew J Ellsworth

An air conditioning unit includes a passage having a heat exchanger; a blower for blowing air through the passage; a blower motor driving the blower in response to a drive signal; an energy recovery ventilator (ERV), the blower drawing outside air from the ERV; and a controller for adjusting the drive signal in a ventilation mode to reduce power used by the blower motor.

Energy recovery ventilator with reduced power consumption

A method and system for operating a modulating furnace from a single-stage thermostat. The furnace control system may include a processor, a gas valve, a variable-speed motor, and a thermostat. The furnace control may execute a thermostat algorithm comprising the steps of: determining if a heating load needs to be satisfied; running burners at an intermediate input rate, a modulated input rate, and a maximum input rate for each respective first, second, and third time intervals until the heating load is satisfied; calculating a heating load requirement as function of the time intervals; and determining an initial input rate for a next cycle based on the calculated heating load requirement.

Thermos at algorithm for fully modulating furnaces

A method for operating a furnace system includes initiating a start sequence comprising starting an inducer fan operative to induce an air flow through a burner assembly, a heat exchanger portion and a collector portion, determining whether an air pressure in the collector portion is above a first threshold value, starting a furnace ignition sequence including providing fuel to the burner assembly, igniting a fuel and air mixture and starting an ignition timer responsive to determining that the air pressure in the collector portion is above the first threshold value, determining whether the ignition timer has expired, determining whether the air pressure in the collector portion is above a second threshold value responsive to determining that the ignition timer has expired, and stopping the provision of fuel to the burner assembly responsive to determining that the air pressure in the collector portion is not above the second threshold value.

Furnace control system and method

A method of controlling a blower motor in a furnace includes applying control signals to the blower motor; determining that a reference airflow through a portion of the furnace is present; determining a reference control signal at which the reference air flow is present; receiving a requested airflow; computing a requested control signal in response to the reference air flow, the reference control signal and the requested airflow; and using the requested control signal to control the blower motor.

Method and system for variable speed blower control

A furnace includes an induced draft blower; an inducer motor driving the induced draft blower; and a furnace control determining a modulation percentage, the furnace control controlling RPM of the inducer motor in response to the modulation percentage.

Method and system for controlling an inducer in a modulating furnace

A pressure switch assembly is used with a furnace controller having a first input and a second input. A first pressure switch is configured to actuate at a first combustion pressure level and is connected to the first input. A second pressure switch is configured to actuate at a second combustion pressure level, and a third pressure switch is configured to actuate at a third combustion pressure level. Pressure signals provided on the second input from at least one of the second pressure switch and the third pressure switch are used by the furnace controller to derive actuation states of the second and third pressure switches.

Pressure switch assembly for a furnace

A method and system for detecting flame rollout is disclosed. The detection system includes a processor programmed to execute a furnace lockout when the flame proving signal is lost three times after successful burner ignition has been established on each of three heating cycles within a predetermined period of accumulated burner on-time. In one embodiment the period of accumulated burner on-time is 60 minutes. The program executed by the processor resides in firmware. The system and method of present invention mitigates the potentially harmful accumulation of flue gasses when flame sense is lost due to flame rollout.

System and method for detecting flame rollout in a furnace

An inducer wheel or impeller in which the hub may be formed by machining, rather than by molding, and which possesses a generally cylindrical cavity having a flattened section without a tapered inner diameter. Consequently, the hub may be mounted on a rotatable shaft having a corresponding flattened portion of a rotatable shaft with relatively small tolerance between the periphery of the shaft and the interior cavity wall of the hub uniformly along the shaft length. A plastic rotor may be molded onto the hub such that the plastic abuttingly contacts the flattened region of the rotatable shaft and surrounds and covers a relatively large peripheral area of the hub. A method of making such an inducer wheel is disclosed, and the inducer wheel made by such a method is also disclosed.

Inducer wheel and method of forming the same

When a single-stage thermostat is appropriately connected to a two-stage cooling system, a microprocessor control activates low and high stages of cooling based on preset parameters. The cooling load requirement is determined and compared to the maximum load requirement that can be satisfied in low-stage cooling mode and the minimum load requirement which can be satisfied in high-stage cooling mode. The desired low-stage cooling time limit is then determined for the next cycle. After the first cycle, the desired low-stage cooling time limit may be equal to zero in which case the next cycle is spent in high-stage cooling mode, or, if greater than zero, the next cycle runs in low-stage cooling mode up to the desired low-stage cooling time limit, with an additional high-stage cooling mode run if the thermostat is not satisfied within the desired time.

Method and apparatus for using single-stage thermostat to control two-stage cooling system

An improved, induced-draft, gas-fired furnace which is adapted to operate at any of a high, medium and low firing rate. A pressure sensing assembly generates differential pressure signals that vary in accordance with the pressure across a heat exchanger assembly. A gas flow control assembly is responsive to the differential pressure signals, and to signals received from the furnace control circuit, to supply gas to the furnace at any of its three different firing rates, the lowest of those said firing rates corresponding to a gas-air mixture which cannot be ignited. The furnace control circuit applies to the circulating air blower, and to the inducer blower, speed controls signals that are so related to one another that the fuel utilization efficiency of the furnace is at least as great during steady state operation at its low firing rate as during steady state operation at its medium firing rate.

Modulating furnace having a low stage with an improved fuel utilization efficiency

An improved, induced-draft, gas-fired furnace which is adapted to operate at any of a high, medium and low firing rate. A pressure sensing assembly generates differential pressure signals that vary in accordance with the pressure across a heat exchanger assembly. A gas flow control assembly is responsive to the differential pressure signals, and to signals received from the furnace control circuit, to supply gas to the furnace at any of its three different firing rates, the lowest of those firing rates corresponding to a gas-air mixture which cannot be ignited. The furnace control circuit applies to the circulating air blower, and to the inducer blower, speed control signals that are so related to one another that the lowest primary wall temperature in the heat exchanger is maintained above the condensation temperature of water during steady state operation of the furnace at its low firing rate.

Modulating furnace having improved low stage characteristics

A method and apparatus for increasing the circulating airflow of induced-draft, gas-fired multi-stage furnaces without creating conditions that result in cold spot corrosion therein. Control circuitry is provided to selectably increase the circulating airflow of the furnace during low stage operation. The control circuitry is arranged so that increases in the magnitude of the circulating airflow of the furnace are accompanied by predetermined increases in the magnitude of the combustion airflow of the furnace. The magnitudes of the circulating and combustion airflows are so related to one another that the temperature at the output of the heat exchanger is maintained at a value which is approximately constant, and which is high enough to assure that water cannot condense thereon. The control circuitry may include a relay or relay-like device that is connected to prevent the high stage solenoid of the gas valve from becoming actuated during low stage operation.

Method and apparatus for preventing cold spot corrosion in induced-draft

A method for adjusting the continuous speed of the blower of a heating and/or cooling system of the type including a thermostat having a mode selector switch which has at least one heating position, a cooling position, and an off position, a fan switch having an on position or state and an auto position or state, and a programmable control device responsive to the thermostat for generating speed select signals for use in setting the speed of the blower motor. The programmable control device is programmed or reprogrammed so that, when the mode selector switch is in its off position or when there is no call for heating or cooling at the thermostat, time dependent movements of the fan switch away from and back to its on position are recognized as requests for changes in the continuous speed of the blower motor. The programmable control device is further programmed or reprogrammed to change the blower speed from one value to the next adjacent value each time the programmable control device recognizes the occurrence of a request for a change in speed.

Continuous fan adjustment method

A combustion air regulating apparatus which is adapted for use with two stage induced draft furnaces and which allows such furnaces to be used with low cost AC inducer motors of the type having one or a small number of nominally fixed operating speeds. A flow restrictor assembly is disposed in fluidic series with the air intake and the exhaust vent to controllably restrict the flow of air through the burner box when the inducer motor operates at its low speed. A pressure sensing assembly is connected to sense a pressure approximately equal to that across the heat exchanger, and to control the flow resistance of the flow restrictor assembly to maintain a sufficient level of excess air when the furnace operates in its low stage. A solenoid valve responsive to the establishment of high stage furnace operation causes the flow restrictor assembly to establish and maintain its minimum flow resistance during operation in that stage.

Growing community of inventors

Indianapolis, IN, United States of America

Kevin D Thompson