×

Method for efficient fan control for electric or gas furnaces and heat pumps in heating mode

  • US 9,797,405 B1
  • Filed: 03/22/2012
  • Issued: 10/24/2017
  • Est. Priority Date: 03/22/2012
  • Status: Active Grant
First Claim
Patent Images

1. A method for controlling a heating system ventilation fan, the method comprising:

  • controlling a fan relay signal from a thermostat to a fan relay, the fan relay normally controlled by a thermostat G terminal to control the ventilation fan to circulate air through a heating system;

    monitoring a heating system operating time defined from when the thermostat is initiating a call for heating until when the thermostat is terminating the call for heating;

    after the thermostat initiates the call for heating, performing at least one action selected from the group consisting of;

    turning on the ventilation fan after an initial delay to circulate air through the heating system,energizing the fan relay normally controlled by the thermostat G terminal to circulate air through the heating system, andwaiting while the heating system is turning on the ventilation fan to circulate air through the heating system and waiting a first period of time P1 with the ventilation fan operating, and after the period of time P1, energizing the fan relay normally controlled by the thermostat G terminal to circulate air through the heating system;

    continuing to circulate air through the heating system and the thermostat continuing calling for heating until a selected thermostat set point temperature is satisfied;

    the thermostat terminating the call for heating when the thermostat set point temperature is satisfied thereby turning off the heating system;

    setting a heating system operation time P3 to the length of time from when the thermostat is initiating a call for heating until when the thermostat is terminating the call for heating;

    computing an extended fan-off delay period of time P2 as a function of the heating system operation time P3 and energizing the fan relay signal for the entire fan-off delay period of time P2, and de-energizing the fan relay signal at the end of the fan-off delay period of time P2.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×