Homeowners with a do-it-yourself attitude often jump into appliance troubleshooting or repair without stopping to determine how doing so may affect the manufacturer's warranty that covers the appliance. Many home appliance warranties specifically prohibit unauthorized troubleshooting or repairs. Performing an unauthorized repair on your furnace may void its manufacturer's warranty, leaving you holding the bag for any future repairs. Contact your furnace manufacturer or consult your owner's manual for additional repair or warranty information.
Following a few simple safety precautions can help to prevent your do-it-yourself appliance troubleshooting or repair process from getting out of hand and resulting in injury. Furnaces are large appliances that are powered by electricity or a combination of gas and electricity; prevent electrical injury by disconnecting all electricity and gas before disassembling your furnace. Locate the gas valve on gas furnaces; turn the valve 90 degrees to shut off the gas supply. Find your home's main electrical service panel, and identify the breaker switch that controls your furnace; flip the switch into the "Off" position.
Disassembling your furnace to access the filter requires no tools and is actually much easier than it sounds. Examine your home furnace to determine the location of the removable service panel, which is usually located on the front or side of the appliance. Feel around the edges of the panel until you feel the small handles or indentations that are used to remove the panel from the furnace cabinet; grab these and lift up on the panel while simultaneously pulling it towards you. Place the removed furnace panel in a safe, out-of-the-way location until your troubleshooting is complete.
Locate Furnace Filter
Peer into the furnace and locate the large metal drum toward the back of the cabinet. Known as the blower chamber, this drum-like component houses the furnace's fan motor. Search for the furnace filter near the supply or return ducts; though the exact furnace filter location can vary by brand and model, it will be located in the general area of the blower chamber. Furnace filters can vary in size; look for a cardboard frame that is approximately 1-inch thick and at least 12 inches wide. The filter may be positioned horizontally or vertically. When you've identified the filter, pull gently on the cardboard frame to remove the filter from the furnace.