Systems and methods of detecting an obstructed furnace air filter using a pressure sensor

Patent metadata

Field	Value
Publication number	US-12092352-B2
Application number	US-202016986476-A
Country	US
Kind code	B2
Filing date	Aug 6, 2020
Priority date	Aug 6, 2020
Publication date	Sep 17, 2024
Grant date	Sep 17, 2024

Abstract

The disclosed technology includes systems and methods for detecting an obstructed air filter in a furnace. The disclosed technology can include a method and system that includes an air inlet, an air filter for filtering particles from air passing through the air inlet, an air moving device, a fuel valve, a burner, a pressure sensor, and a controller in communication with the pressure sensor and configured to output an alarm signal when the controller receives differential pressure data from the pressure sensor that indicates that the air filter is obstructed.

First claim

What is claimed is:

1. A non-transitory, computer-readable medium having instructions stored thereon that, when executed by one or more processors, cause a system to:
receive a start signal;
determine whether a pressure sensor switch of a pressure sensor is open or closed after receiving the start signal;
in response to determining that the pressure sensor switch is open after receiving the start signal, determine whether the pressure sensor switch is open or closed after a first predetermined amount of time elapses from receiving the start signal;
in response to determining that the pressure sensor switch is closed after the first predetermined amount of time elapses, determine a differential pressure across an air filter associated with a burner;
determine whether the differential pressure across the air filter is less than a predetermined threshold differential pressure for the first predetermined amount of time;
determine, at a first time interval, that the pressure sensor switch is closed after determining that the differential pressure across the air filter is less than the predetermined threshold differential pressure;
determine, at a second time interval, that the air filter is at least partially obstructed in response to determining that the differential pressure across the air filter is greater than or equal to the predetermined threshold differential pressure;
output a first alarm signal indicating that the air filter is at least partially obstructed;
determine, at a third time interval, that the differential pressure across the air filter is greater than or equal to a predetermined high-limit threshold differential pressure for a second predetermined amount of time, wherein the second predetermined amount of time is greater than or equal to the first predetermined amount of time;
determine that the air filter is at least partially obstructed at the third time interval; and
output a first control signal for a fuel valve associated with the burner to at least partially close.

2. The non-transitory, computer-readable medium of claim 1 , wherein the instructions, when executed by the one or more processors, further cause the system to:
in response to determining that the pressure sensor switch is closed after receiving the start signal, output a second alarm signal to indicate that the pressure sensor switch has malfunctioned.

3. The non-transitory, computer-readable medium of claim 2 , wherein the instructions, when executed by the one or more processors, further cause the system to:
in response to determining that the pressure sensor switch is open after the first predetermined amount of time, output the second alarm signal to indicate that the pressure sensor switch has malfunctioned.

4. A non-transitory, computer-readable medium having instructions stored thereon that, when executed by one or more processors, cause a system to:
determine a start signal;
determine whether a pressure sensor switch of a pressure sensor is open or closed after receiving the start signal;
in response to determining that the pressure sensor switch is open after receiving the start signal, determine whether the pressure sensor switch is open or closed after a first predetermined amount of time elapses from receiving the start signal;
in response to determining that the pressure sensor switch is closed after the first predetermined amount of time elapses, determine a differential pressure across an air filter associated with a burner;
determine whether the differential pressure across the air filter is less than a predetermined threshold differential pressure for the first predetermined amount of time;
determine, at a first time interval, that the pressure sensor switch is closed after determining that the differential pressure across the air filter is less than the predetermined threshold differential pressure;
determine, at a second time interval, that the air filter is at least partially obstructed in response to determining, that the differential pressure across the air filter is greater than or equal to a predetermined threshold differential pressure for a first predetermined amount of time;
output a first alarm signal indicating that the air filter is at least partially obstructed;
determine, at a third time interval, that the differential pressure across the air filter is greater than or equal to a predetermined high-limit threshold differential pressure for a second predetermined amount of time, wherein the second predetermined amount of time is greater than or equal to the first predetermined amount of time;
determine that the air filter is at least partially obstructed at the second time interval; and
output a first control signal for a fuel valve associated with the burner to at least partially close.

5. The non-transitory, computer-readable medium of claim 4 , wherein:
the instructions, when executed by the one or more processors, further cause the system to:
output a second control signal for a fuel valve associated with the burner to at least partially close.

6. The non-transitory, computer-readable medium of claim 4 , wherein:
the instructions, when executed by the one or more processors, further cause the system to:
output a second control signal for a fuel valve associated with the burner to at least partially close.

7. The non-transitory, computer-readable medium of claim 6 , wherein:
output a third control signal for a fuel valve associated with the burner to at least partially close.

8. A furnace system capable of detecting an obstructed air filter, the furnace system comprising:
an air inlet;
an air filter for filtering particles from air passing through the air inlet;
an air moving device configured to move the air from the air inlet, through the air filter, and toward a combustion chamber;
a fuel valve configured to direct fuel into the air being moved toward the combustion chamber;
a burner configured to create a flame by burning a mixture of the fuel and the air;
a pressure sensor configured to detect a differential pressure across the air filter; and
a controller configured to:
receive a start signal;
determine whether a pressure sensor switch of a pressure sensor is open or closed after receiving the start signal;
in response to determining that the pressure sensor switch is open after receiving the start signal, determine whether the pressure sensor switch is open or closed after a first predetermined amount of time elapses since receiving the start signal;
in response to determining that the pressure sensor switch is closed after the first predetermined amount of time elapses, determine a differential pressure across an air filter associated with a burner;
determine, at a first time interval, that the pressure sensor switch remains closed in response to determining that the differential pressure across the air filter is less than a predetermined threshold differential pressure for the first predetermined amount of time;
determine that the differential pressure across the air filter is greater than or equal to a predetermined threshold differential pressure for a second predetermined amount of time;
in response to determining that the differential pressure across the air filter is greater than or equal to the predetermined threshold differential pressure for the second predetermined amount of time, determine that the air filter is at least partially obstructed at a second time interval;
output a first alarm signal indicating that the air filter is at least partially obstructed;
determine, at a third time interval, that the differential pressure across the air filter is greater than or equal to a predetermined high-limit threshold differential pressure for a third predetermined amount

Assignees

• Rheem Mfg Co

Inventors

• Farley Darryl
• Taylor Christopher

Classifications

• F24F11/52

  Indication arrangements, e.g. displays · CPC title

• F23N2225/06

  for determining flow · CPC title

• B01D46/0086

  Filter condition indicators · CPC title

• F24H3/006 Primary

  using fluid fuel · CPC title

• B01D2279/00

  Filters adapted for separating dispersed particles from gases or vapours specially modified for specific uses · CPC title