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Cleaning & Maintaining a Vented Gas Heater

vented gas heater
Williams Furnace Company 3003 30,000 BTU Direct Vent Wall Furnace

For their ease of installation and promise of even, consistent heat, vented gas furnaces are popular heating options for both residential and commercial spaces. As with any major appliance, your vented gas heater requires routine cleaning and maintenance to ensure better safety and function throughout high Autumn and winter. Such a routine involves a thorough inspection and cleaning of the inside of the furnace, as well as testing and, if necessary, readjusting the burner flame.

General maintenance and upkeep should be conducted annually, at the start of each heating season. We recommend a professional be hired to perform these checks unless the homeowner is a highly skilled professional him/herself with experience in electrical, gas, or maintenance work.

Since the process is fairly involved and requires detailed knowledge of what to look for and consider, we at Total Home Supply have assembled a guide to the cleaning and maintenance of both direct-vent and b-vent gas heaters. The unit’s manual should still be considered before undertaking any maintenance routine, however, as guidelines and instructions of use may vary from unit to unit.

A Note on Safety

Using your Furnace

When handling any major appliance, safety is the number-one priority. It is important to always keep the area around the furnace free of any combustible materials, including gasoline or other flammable liquids and vapors, and to not place obstructive furniture too close to the unit while it is in use. As a general rule, furniture and other items should be placed no closer than four feet from the front of the cabinet and two feet from either side, lest the combustion and ventilation air supply becomes blocked. Nothing should ever be placed in or on the furnace cabinet, as doing so poses a dangerous fire hazard.

Preparing for Routine Inspection and Cleaningfurnace1

Safety precautions should be taken when preparing to clean the unit, as well. Components inside your unit’s furnace cabinet are live, and so it is extremely important to switch off your electric power supply at the disconnect switch, fuse box, or service panel before removing any access doors. Although these units are gas-powered and electricity is only required with use of an optional blower, the inside of your furnace still contains electrical wiring and failing to switch it off can result in serious bodily harm or death.


Cleaning the Exterior of the Furnace

As with any indoor surface, the exterior of your furnace requires routine dusting and cleaning. Because dust and dirt on the exterior of the unit often finds its way inside the unit, this is an important step in maintaining the overall health and function of your furnace.

To clean the outside of the furnace, simply wipe down the surface with a damp rag, being careful not to get any moisture inside the vents. Furnaces are typically finished in a heat-resistant powder paint, so never use any abrasive cleaners or try to repaint your unit with wall paint. Furnace dusting/cleaning can, of course, be done by the homeowner, and should take place as often as you would dust or clean any other surface in your home.

Cleaning the Interior of the Furnace

After the electrical power supply has been shut off in accordance with the guidelines listed above, carefully remove any access doors or panels to reveal the working parts of the furnace cabinet.

The inside of each furnace will look slightly different, depending on whether it is a direct-vent furnace, which pulls and vents air directly through an outside wall, or a B-vent furnace, which vents air through the ceiling. All furnaces have the same main components, however, including a fan (if using the optional blower), a burner, and exposed air passages, and these are the parts that need inspection and cleaning.

If the unit has the optional blower attached, clean the fan blades and fan motor of any lint, dust, or dirt. This can be easily done with a brush.

Cleaning the Venting System

The unit’s venting system is most likely the dirtiest part of the furnace, as air pulled in from outside the unit contains debris that can get stuck all along the inside of the vent pipe. Locate the vent pipe and, wearing a dust mask and rubber gloves, open it with a screwdriver. Use a brush and a damp rag to clean out any debris. A vacuum cleaner can also be used to clean out any excess material. Use an undone wire hanger or metal stake to prod around inside the pipe to check for blockages, and inspect the pipe for any rust or holes. If the vent pipe is rusted or damaged, it will have to be replaced.

Re-seal the vent pipe when you are done and turn your attention to the unit’s burner compartment. This is another place where lint, dust, and dirt build-up is common. To clean, disconnect the gas line inside the combustion chamber, and work in and around the burner with a vacuum. Inspect the burner box gasket for damage, and replace if needed.

Vented gas furnace maintenance can help avoid common furnace issues.

furnace2 Testing the Furnace

Testing the Flame

To test the furnace for proper function, reconnect the gas line and light the pilot according to the directions in the unit’s manual (pilot ignition can differ from model to model). Notice the size of the flame, which should surround the generator tip 3/8″ – 1/4″ for B-vent furnaces, 5/8″ – 1/2″ for direct-vent furnaces. Also note the shape and color of the flame, which should be a soft, clear blue cone with a blueish-red or blueish-violet outer mantle.

The build-up of foreign material (dust, lint, etc.) in the burner’s primary air opening can interfere with proper air gas mixture, which causes the flame to appear yellow. A yellow flame is not normal and can produce carbon monoxide and soot, which is incredibly dangerous and potentially deadly. The routine cleaning detailed above should work to prevent the build-up associated with an abnormal flame, but cleaning around the burner, too, can accidentally mis-adjust the pilot.

Readjusting the Burner

To remedy this, simply re-adjust the pilot until the flame is the correct size, shape, and color. Again, this should be done according to the directions in the particular furnace’s manual, as pilot operation can differ between models.

When all inspections and cleanings are done, replace or close all access doors and panels and switch electricity back on. Your vented furnace is ready for winter!

If you have any further questions regarding the cleaning and maintenance of your vented gas heater, please do not hesitate to contact us at 1-877-847-0050 and speak to one of our qualified representatives.

Kristen Turner

Featured blogger for Total Home Supply.

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