Method of and system for flame sensing and diagnostic

Patent metadata

Field	Value
Publication number	US-10145584-B2
Application number	US-201815968992-A
Country	US
Kind code	B2
Filing date	May 2, 2018
Priority date	Feb 5, 2015
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

A method of determining presence of a flame in a furnace of a heating, ventilation, and air conditioning (HVAC) system. The method comprises determining, using a controller, whether a processor signal (G) is active, responsive to a determination that the processor signal (G) is active, determining, using the controller prior to assertion of a flame-test input control signal, an output state of a first comparator, responsive to a determination that the output state of the first comparator is high, determining, using the controller prior to assertion of the flame-test input control signal, an output state of a second comparator, and responsive to a determination that the output state of the second comparator is low, transmitting, using the controller, a notification that a flame is present.

First claim

What is claimed is:

1. A method of determining presence of a flame in a furnace of a heating, ventilation, and air conditioning (HVAC) system, the method comprising:
determining, using a controller, whether a processor signal (G) is active;
responsive to a determination that the processor signal (G) is active, determining, using the controller prior to assertion of a flame-test input control signal, an output state of a first comparator;
responsive to a determination that the output state of the first comparator is low, determining, using the controller prior to assertion of the flame-test input control signal, the output state of the second comparator; and
responsive to a determination that the output state of the second comparator is low, transmitting, using the controller, a notification that a problem exists.

2. The method of claim 1 further comprising:
responsive to a determination that the output state of the second comparator is high, transmitting, using the controller, a notification that no flame is present;
asserting the flame-test input control signal;
determining, using the controller, whether the output state of the first comparator flips from low to high and the output state of the second comparator flips from high to low;
responsive to a determination that the output state of the first comparator does not flip from low to high and the output state of the first comparator does not flip from high to low, transmitting, using the controller, a notification that a flame is not present and no problem exists; and
responsive to a determination that the output state of the first comparator flips from low to high or the output state of the second comparator flips from high to low, transmitting, using the controller, the notification that the problem exists.

3. The method of claim 1 further comprising:
responsive to a determination that the output state of the first comparator is high, determining, using the controller prior to assertion of the flame-test input control signal, an output state of a second comparator; and
responsive to a determination that the output state of the second comparator is high, transmitting, using the controller, a notification that a problem exists.

4. The method of claim 1 further comprising:
asserting the flame-test input control signal;
determining, using the controller, whether the output state of the first comparator flips from high to low and the output state of the second comparator flips from low to high;
responsive to a determination that the output state of the first comparator does not flip from high to low or the output state of the second comparator does not flip from low to high, transmitting, using the controller, a notification that a problem exists;
responsive to a determination that the output state of the first comparator flips from high to low and the output state of the second comparator flips from low to high, deasserting the flame-test input control signal;
determining, using the controller, whether the output state of the first comparator flips from low to high and the output state of the second comparator flips from high to low;
responsive to a determination that the output state of the first comparator does not flip from low to high or the output state of the second comparator does not flip from high to low, transmitting, using the controller, the notification that the problem exists; and
responsive to a determination that the output state of the first comparator flips from low to high and the output state of the second comparator flips from high to low, transmitting, using the controller, a notification that a flame is present and no problem exists.

5. The method of claim 1 further comprising:
responsive to a determination that the output state of the second comparator is low, transmitting, using the controller, a notification that a flame is present.

6. The method of claim 1 further comprising:
responsive to a determination that the processor signal (G) is inactive, determining, using the controller prior to assertion of the flame-test input control signal, the output state of the first comparator;
responsive to a determination that the output state of the first comparator is low, determining, using the controller prior to assertion of the flame-test input control signal, the output state of the second comparator;
responsive to a determination that the output state of the second comparator is high, transmitting, using the controller, a notification that a flame is not present; and
responsive to a determination that the output state of the second comparator is low, transmitting, using the controller, a notification that a problem exists.

7. The method of claim 6 further comprising:
asserting the flame-test input control signal;
determining, using the controller, whether the output state of the first comparator flips from low to high and the output state of the second comparator flips from high to low;
responsive to a determination that the output state of the first comparator does not flip from low to high and the output state of the second comparator does not flip from high to low, transmitting, using the controller, a notification that a flame is not present and no problem exists; and
responsive to a determination that the output state of the first comparator flips from low to high or the output state of the second comparator flips from high to low, transmitting, using the controller, the notification that the problem exists.

8. The method of claim 6 further comprising:
responsive to a determination that the output state of the first comparator is high, determining, using the controller prior to assertion of the flame-test input control signal, the output state of the second comparator; and
responsive to a determination that the output state of the second comparator is low, transmitting, using the controller, the notification that the problem exists.

9. The method of claim 8 further comprising:
responsive to a determination that the output state of the second comparator is high, transmitting, using the controller, a notification that a flame is present.

10. The method of claim 9 further comprising:
asserting the flame-test input control signal;
determining, using the controller, whether the output state of the first comparator flips from high to low;
responsive to a determination that the output state of the first comparator does not flip from high to low, transmitting, using the controller, the notification that the problem exists;
responsive to a determination that the output state of the first comparator flips from high to low, determining, using the controller, whether the output state of the second comparator does not flip from high to low;
responsive to a determination that the output state of the second comparator does flip from high to low, transmitting, using the controller, the notification that the problem exists; and
responsive to a determination that the output state of the second comparator does not flip from high to low, transmitting, using the controller, a notification that a flame is present and no problem exists.

11. The method of claim 1 , wherein the controller comprises a memory having a series of operating instructions stored therein for directing operation of the controller.

12. A circuit for determining presence of a flame, the circuit utilized in a printed circuit board (PCB) of a heating, ventilation, and air conditioning (HVAC) system, the circuit comprising:
a flame detect circuit;
a tank circuit;
a first comparator;
a second comparator; and
a controller operatively coupled to the flame detect circuit, the tank circuit, th

Assignees

• Lennox Ind Inc

Inventors

• Engler Michael

Classifications

• F23N2241/02

  Space-heating · CPC title

• F23N2231/06

  for flame failures · CPC title

• F23N5/265

  using electronic means · CPC title

• F23N5/123

  using electronic means · CPC title

• F23N5/242

  using electronic means · CPC title