If you are unfamiliar with your furnace or have any doubts about the maintenance steps, have your service person take you through all of the procedures.

• Testing and cleaning steps that should be performed only by a qualified furnace inspector are listed separately. Perform a draft hood test for combustion air. Turn off your main electrical furnace switch before proceeding with the check-up.
• Clean or replace the furnace filter. Replace filters monthly when your furnace or central air conditioner is in use. Seal the filter opening with duct tape.
• Check the belt between the blower and the motor. Replace it if it is frayed or worn. The belt should give way to the touch by about one inch. If it doesn't, adjust the tension.
• Carefully clean and oil the blower motor. Clean the blower fan monthly to remove dust accumulations from the blades and motor body. Check to make sure that the door to the blower cabinet is closed. Make sure the power to the motor is off when you clean it.
• Vacuum register grilles and gently clean the thermostat. Remove grilles and check for obstructions in all ducts and in the cold air returns.
• Tape seams in ducts and check to make sure that all ducts are connected.

Your qualified furnace contractor or service provider should include these steps in the inspection and cleaning of your furnace. An oil furnace should be inspected and cleaned yearly and a gas furnace should be tuned-up every other year.

• Perform a test for carbon monoxide. If carbon monoxide is found, have the situation thoroughly diagnosed and corrected.
• Inspect and clean the flue, the chimney, and the connection from the furnace to the chimney. Look for obstructions, cracks, or other deterioration.
• Check the combustion air inlet for proper sizing. Make sure that the air inlet is not blocked and that the supply of combustion air is sufficient.
• Check burner performance and make adjustments if needed. Clean burners to maintain efficiency and safety. Check fuel supply and the filter in the fuel supply line (applicable to oil systems only).
• Look for and remove any dirt, soot, or rust in the heat exchanger. The heat exchanger should be checked using a non-destructive method. Inspect for cracks, seam failure, and warpage.
• Have your inspector perform a flue gas analysis and give you the results to keep for future reference. The results will help you determine the efficiency of your system.
• Test all controls for proper operation. If possible, optimize on-off settings for energy efficiency.

All of the items listed under Check-List for Professional Furnace Inspectors should also be completed for boiler systems. Additional steps specific to boilers are listed below. Boilers fueled by oil should be inspected yearly and gas-fired boilers should be inspected every other year. If you are familiar with your boiler system, you may want to perform the following maintenance steps yourself. It is recommended that a qualified boiler inspector show you how to do the steps your first time through. Boiler systems are configured in such variety that only a few general maintenance tips, listed below, apply to the majority of boiler systems.

• Oil the pump to allow smooth operation and prevent the motor from overheating.
• Remove dirt and grime from the pump to insure an efficient heat transfer.
• Bleed radiators by opening valves to release pockets of air. Once the water is flowing steadily, you'll know that you have let all of the unwanted air escape.
• After radiators have been bled, check the temperature/pressure gauge(s) and maintain the boiler's proper water level.
• Check the expansion tank to insure that it has proper air and water levels to allow room for expansion.

Source: Energy Information Center, Minnesota Department of Commerce