The supplies needed to service a furnace are foil tape, an air filter for the furnace model and an oil filter and nozzle for oil-powered systems. The tools needed are a screwdriver, wire brush, shop vacuum, strap wrench and a combustion analyzer. A multimeter or ohm meter is also useful.
All furnace maintenance should begin by shutting off the electrical power to the unit, either by switch or cut off device or by tripping the main breaker on the house electrical panel. Flue pipe inspection, an oil change on oil-powered models and air filter changes are next. These are followed by burner inspection and cleaning, an efficiency check and combustion analysis, and an electrical meter check of the ignitor and flame sensor. Checking the condensation lines is important because over 90 percent of furnace problems are caused by clogged or non-functioning condensation lines.