Gas Furnace Inspections, Service, and Maintenance Tips
Gas furnaces should be inspected annually, preferably before the beginning of the heating season, by a qualified service technician to ensure continued safe operation. The inspection should include the following:
Caution
Always carefully read the service and maintenance instruction for the furnace first. As a rule, the electrical power is shut off first at the disconnect switch if service or an inspection is to be performed. After switching off the power, turn off the gas valve.
• Inspect the vent pipe for water accumulation, sagging piping, dirt, loose joints, and damage.
• Check the return air duct for a tight connection to the furnace. The duct connection must provide an airtight seal at the furnace and must terminate at its other end outside the room or space where the furnace is located.
• Inspect the furnace wiring for burnt or damaged wires and loose connections.
• Inspect interior and exterior furnace surfaces for dirt or water accumulation.
• Make sure the blower access door is tightly closed.
• Inspect the burners for dirt, rust, or signs of water.
• Make sure the fresh air grilles and louvers are open, clean, and unobstructed.
• Inspect and clean the condensate traps and drain to prevent water accumulation in the furnace.
• Inspect the blower wheel and remove any debris.
• Check the furnace support and base. The base of the furnace must form a tight seal with the support.
If the above items all pass inspection, restore power and start the furnace according to the furnace manufacturer’s instructions. It will involve first turning on the gas valve and then turning on electrical power to the furnace. Continue the inspection as follows:
Caution
If you smell gas, call the local gas company immediately from a telephone outside the house and follow their instructions.
• Run the furnace and observe its operation. The furnace should operate smoothly and quietly. Check the vent pipe and return duct to make sure they are not leaking.
• Analyze the combustion gases to make sure they meet the furnace manufacturer’s specifications.
Note
Although the hot surface igniter used in a hot surface ignition (HSI) gas furnace may be made of a material (such as silicon carbon) capable of resisting the high temperatures encountered when firing the gas-air mixture, these igniters are fragile and easily damaged if not handled carefully. The damage most commonly occurs during shipment from the furnace manufacturer or supplier, or during installation. The damage is not always visible to the naked eye and a cracked igniter initially can function according to specifications. However, eventually, its operating efficiency will degrade and its service life will be much shorter. Igniter damage too small to see can be discovered by checking for inconsistencies in its glow pattern immediately after installation.