Variable capacity furnace control

A furnace, comprising:

• a burner configured to generate combustion products from a fuel and an oxidant;
• a fuel valve configured to be controlled to a target setting over a range of settings to modulate an amount or flow rate of the fuel supplied to the burner;
• and
• a controller configured to:
• determine, based on a first value indicative of whether an indoor temperature is progressing toward a set point over time and based on a second value indicative of a temperature differential between the set point and the indoor temperature, the target setting;
• and
• control the fuel valve to the target setting.

One or more tangible, non-transitory, computer-readable media storing instructions thereon that, when executed by one or more processors, are configured to cause the one or more processors to:

• receive a first input indicative of a temperature differential between a set point of a thermostat and an indoor temperature of an indoor space being heated by a variable capacity furnace;
• receive a second input indicative of whether the indoor temperature is progressing toward the set point or away from the set point over time;
• determine, based on the first input and the second input, a target setting of a variable capacity fuel valve configured to modulate an amount or flow rate of a fuel supplied to a burner assembly of the variable capacity furnace;
• and
• control the variable capacity fuel valve to the target setting.