Fan speed on a gas furnace should be set based on what?

Setting the fan speed on a gas furnace is critically linked to the temperature rise specified on the data plate. The data plate provides essential information about the furnace’s performance, particularly the acceptable temperature rise, which indicates how much the air temperature should increase as it passes through the heat exchanger.

This temperature rise is typically measured in degrees Fahrenheit and is crucial for ensuring the furnace operates efficiently and safely. If the fan speed is set too high, the air may not have enough time to absorb heat, leading to an inadequate temperature rise, which can cause poor heating performance and could potentially harm the heat exchanger. Conversely, if the fan speed is too low, the air could get excessively hot, possibly leading to safety issues or damage to the furnace.

By following the temperature rise guidelines on the data plate, technicians can set the fan speed to achieve the optimal balance of efficiency and effectiveness in heating, ensuring comfort and safety in the home.