Furnace for a rooftop unit

One or more tangible, non-transitory machine-readable media comprising processor-executable instructions to:

• receive feedback from a first sensor indicative of ambient temperature;
• compare the feedback indicative of the ambient temperature to a temperature threshold;
• operate a furnace of a heating, ventilating, and air conditioning (HVAC) system in a first operating mode when the ambient temperature exceeds the temperature threshold;
• and
• operate the furnace of the HVAC system in a second operating mode when the ambient temperature is at or below the temperature threshold, wherein the furnace operates above a condensation temperature of an exhaust gas when in the second operating mode, such that the exhaust gas does not condense when the furnace operates in the second operating mode.

A method of operating a furnace of a heating, ventilating, and air condition (HVAC) system, comprising:

• receiving feedback from a sensor indicative of ambient temperature;
• comparing the feedback indicative of the ambient temperature to a temperature threshold;
• operating a furnace of a heating, ventilating, and air conditioning (HVAC) system in a first operating mode when the ambient temperature exceeds the temperature threshold;
• and
• operating the furnace of the HVAC system in a second operating mode when the ambient temperature is at or below the temperature threshold, wherein the furnace operates above a condensation temperature of an exhaust gas when in the second operating mode, such that the exhaust gas does not condense when the furnace operates in the second operating mode.