COMBUSTION BLOWER CONTROL FOR MODULATING FURNACE
First Claim
Patent Images
1. A method of operating a combustion appliance that includes a variable speed combustion blower and a pressure switch, the method comprising:
- determining an expected combustion blower speed at which the pressure switch is expected to change state;
detecting, during operation of a combustion cycle, that the pressure switch does not change state at the expected combustion blower speed;
temporarily adjusting the expected combustion blower speed to a temporary combustion blower speed at which the pressure switch changes state; and
operating the combustion appliance using the temporary combustion blower speed.
3 Assignments
0 Petitions
Accused Products
Abstract
A furnace includes a combustion blower and one or more pressure switches. In some cases, the one or more pressure switches may be used to calculate one or more operating points for the combustion blower. Additional operating points may be calculated by interpolation and/or extrapolation, as appropriate. The furnace may temporarily alter these operating points as necessary to keep the furnace safely operating in response to minor and/or transient changes in the operating conditions of the furnace.
72 Citations
23 Claims
-
1. A method of operating a combustion appliance that includes a variable speed combustion blower and a pressure switch, the method comprising:
-
determining an expected combustion blower speed at which the pressure switch is expected to change state; detecting, during operation of a combustion cycle, that the pressure switch does not change state at the expected combustion blower speed; temporarily adjusting the expected combustion blower speed to a temporary combustion blower speed at which the pressure switch changes state; and operating the combustion appliance using the temporary combustion blower speed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A method of calibrating a variable speed combustion blower disposed of an appliance having a first pressure switch and a second pressure switch, the method comprising:
-
changing the blower speed of the combustion blower until the first pressure switch changes state, thereby determining a first switch state change speed; calculating a first operating point based at least in part on the first switch state change speed; changing the blower speed until the second pressure switch changes state, thereby determining a second switch state change speed; calculating a second operating point based at least in part on the second switch state change speed; and calculating a third operating point based at least in part on the first switch state change speed and the second switch state change speed. - View Dependent Claims (16, 17, 18, 19, 20, 21)
-
-
22. A controller configured to control a combustion appliance that includes a burner, a gas valve configured to provide gas to the burner, a low pressure switch and a high pressure switch, the low and high pressure switches, and a combustion blower, the controller configured to:
-
calibrate the combustion blower by altering a speed of the combustion blower to determine blower speeds at which the low and high pressure switches open and close; determine, via the low pressure switch and/or the high pressure switch, when operating conditions have changed such that the low pressure switch and/or the high pressure switch do not close at expected combustion blower speeds; and temporarily changing the speed of the combustion blower so that the low and/or high pressure switch, as appropriate, close. - View Dependent Claims (23)
-
Specification