DIY Furnace Maintenance
What is routine maintenance on a furnace?
Routine maintenance on a furnace (gas) includes:
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Inspection of the burner flames. The flames should be even across the burner openings and blue in color. Flames with a yellowish tint indicate that the burners are dirty.
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Cleaning the burners (if necessary) Cleaning the burners is easy but disassembling them and removing them from the furnace may pose some minor issues for homeowners with minimum DIY skills. Newer furnace models typically are more owner-serviceable. With the burners removed, use steel wool or a wire brush to scrub the surface, taking care not to damage the surface ignitor behind the first burner. Use compressed air to blow loosened debris from the burners and the fins surrounding them.
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Clean the blower. The blower, also called the “squirrel cage,” is easy to remove on most units, and on some models, removal might not even be necessary. Blow compressed air or brush the fan blade fins thoroughly and vacuum the debris.
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Change the furnace filter. If your unit has its own filter, change it every three months at minimum, and change it whenever you change the return air duct filters throughout the house.
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Tasks you can perform less often include:
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Clean the flame sensor. Every year or so, check the flame sensor for residue that can eventually lead to a failure of your system to light. Using low-grit sandpaper or an emery board, lightly scrub the shaft clean.
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Dust the hot surface igniter. (But don’t touch it!) If your system does not have a pilot light, it has a hot surface igniter. Blow it clean with the straw from a compressed air can.
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Check the integrity of the drive belt. The looser the belt, the slower the blower will turn. Ideally, if you press on the belt, the deflection should be between 1/2” to 3/4”. Replacing a belt is generally simple, but some units may have quirky design elements that crowd the space needed to apply wrenches.
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Lubricate bearings. Newer furnaces have self-lubricating bearings, but older units have oil holes around the fan motor. Simply adding a few drops of standard lubricating oil (like 3-in-1) will keep the shaft spinning unhindered.
Routine maintenance on an electric furnace.
An electric furnace utilizes a heating coil to create heat, and maintaining the connections to the heating coil are of primary importance. Dual fuel systems have gas burners and an electric coil, and many systems with a heat pump include a heater coil when extra heat is needed during extreme cold spells.
Many of the procedures for maintaining an electric furnace are identical to those for maintaining a gas furnace, primarily procedures for blower fan maintenance and ductwork. However, there are a few procedures specific to electric furnaces to follow. Above all, with voltages of 220 volts or more, making sure the system is disconnected at the breaker box is crucial. We do not recommend going beyond the basics, and especially advise against trying to clean any electric component.
So for the homeowner, the main job is inspection, and taking note of any changes in how the system operates, paying attention to things like poor heat quality, odd noises and odd smells. Do not touch any components that conduct electricity (even if you have disconnected the power). It’s best to schedule professional maintenance for the work, but you can help by performing these basic tasks:
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Check for dust and deterioration on all surfaces.
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Check for standing water, drips or moisture on any surface.
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Change the return air duct filter regularly. (This one procedure, at least, is a DYI operation.)
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Remove the thermostat cover and check for loose wires and discolored connection posts.
Is a furnace leaking water dangerous?
A furnace leaking water is dangerous to individuals whose health can easily be compromised by exposure to mold. In addition to posing problems for people, a leaking furnace can self-destruct over time.
High efficiency furnace moisture collects around the second heat exchanger, where condensation is part of the heat exchange process. Excess condensation is drained via a condensate pump into a floor drain or drainage pipe. Leaks occur when the drain hose becomes clogged, or when the reservoir (inducer assembly) develops a crack.
Leaking may also result from a cracked or loosely connected condensate drain line.
In most cases, a leaking furnace should not be considered a DYI project. The source of leaks can be hard to pin down, since water may drip in one place, but run out in another, but one requiring a trained technician.