Furnace runs but produces insufficient heat; home never reaches set temperature.

Safety: Turn off power before removing panels.

Steps:

• Replace filter: Install a new filter of the correct size and MERV rating.
• Check registers: Ensure all supply and return registers are open and unobstructed.
• Verify blower speed: On PSC models, confirm the heating speed tap is set correctly on the control board per Keeprite documentation.
• Inspect burners: Look for uneven or small flames; if present, have burners cleaned and gas input checked by a technician.

Gas input and combustion checks must be done professionally.