Appliances
Compared to oil burners, natural gas and propane are cleaner and have fewer operational difficulties. The common problems that affect gas furnaces are usually related to the thermocouple, pilot light, or electrical components.
Most gas furnaces come with control shutoffs to prevent gas leaks, but they are not always reliable. If you smell gas in your house, do not attempt to turn any lights on or off, or the gas leading to the furnace. Leave the house immediately, leaving the door open, and call the gas company or the fire department to report the leak. Do not go back into your home.
 © 2006 Publications International, Ltd. Gas furnaces typically have few operational issues, with problems usually related to the pilot light, thermocouple, or electrical system. |
Some gas furnaces and heaters have a plug-type door that covers the pilot light assembly. To access the pilot burner, pull the door out of the furnace housing. On other units, remove the panel covering the pilot and gas burners.
The pilot light controls, reset buttons, gas valves, and thermocouple are typically located in an assembly at the front of the furnace. The furnace limit switch can be found on the plenum or main duct junction on the upper housing of the furnace.
To save time, it is best to identify the exact problem with your furnace before attempting to fix it. Check the chart on the next page to find the possible solutions to your furnace problems.
For more information on home repair, visit the following links.
- Furnace Maintenance: Learn the steps to keep your furnace in prime condition and save time and money.
- Major Appliance Repair: Fix other machines in your house besides the furnace.
- Small Appliance Repair: Learn how to fix small appliances like toasters and blenders.
- Thermostat Maintenance: Check your thermostat to make sure there’s actually a problem with your heating system, and learn to calibrate it properly.
secure access panels.
damaged.
needs lubrication.
ports, if available.
properly sized.
assess and resize ductwork.
Conclusion
If you’re having trouble with your gas furnace or gas heater, use this troubleshooting chart to help pinpoint the issue and find a solution. Many problems can be fixed easily, but don’t hesitate to call a professional if necessary. With proper maintenance and attention, your gas furnace or gas heater should work efficiently for years to come.
Ensure that access panels are securely fastened. If the belts are sticking, worn, or damaged, then spray them with belt dressing or replace them. If the blower belts are too loose or too tight, then adjust them accordingly. If the motor and/or blower needs lubrication and has oil ports, then lubricate them. If the burner is dirty, then call a professional. The pilot light is important for the furnace to function properly. To learn how to light a furnace pilot light, see the next page. For more home repair articles, check out the links provided.
How To Light a Furnace Pilot Light
To check the pilot light, you will need matches and a fine wire. Follow the manufacturer’s instructions to relight the pilot. If there are no instructions, then follow these general steps:
To relight a pilot light, the first step is to locate the pilot light assembly, which usually includes a gas valve with on, off, and pilot settings. Next, turn the valve to the off position and wait for three minutes. Then, switch the valve to the pilot setting and hold a lighted match to the pilot opening while pushing the reset button on the pilot control panel. Keep the button depressed until the pilot flame burns brightly, then switch the valve to the on position. If the pilot flame won’t stay lit, the opening may be clogged and should be cleaned with a piece of fine wire. If it still won’t stay lit after multiple attempts, there may be a faulty thermocouple, and a professional service person should be called. Some furnaces don’t have a pilot light and use an electric ignition system instead. If this system malfunctions, it’s best to call a professional. To replace a faulty thermocouple, locate it near the pilot light burner and tighten the nut with a wrench. If that doesn’t work, replace it with a new one of the same type. To do this, unscrew the copper lead and connection nut, insert the new thermocouple, and screw the bracket nut and connection nut into place, being careful not to over-tighten them. For more home repair articles, check out the provided links.
The thermocouple is placed beside the pilot light and is secured by a bracket. The steel tube is positioned upwards while the copper lead is pointing downwards. This is a safety feature that is necessary for the furnace to function properly. Another safety control switch is the limit switch which is located below the plenum. Its main function is to shut off the burner if the plenum gets too hot. It also turns off the blower when the temperature drops to a certain level after the burner has shut off. If the blower runs continuously, it is either because the blower control on the thermostat has been set to ON or the limit control switch needs adjustment. It is important to check the thermostat first and change the blower control to AUTO if it has been set to ON. If the blower control is already on AUTO, then the limit switch needs to be adjusted.
In order to adjust the switch, first remove the cover of the control. Beneath it, you will find a toothed dial with one side labeled LIMIT, which should not be touched. The other side of the control is labeled FAN and has two pointers. The blower turns on at the upper pointer setting and off at the lower pointer setting. The pointers should be set approximately 25 degrees apart, with the upper pointer at around 115 degrees Fahrenheit and the lower one at about 90 degrees Fahrenheit. If you smell gas during these repairs, address the leak immediately. Instructions on how to find gas leaks can be found on the next page. For more home repair articles, check out the links provided.
To ensure the safe use of a gas furnace, it is important to maintain a steady flow of fuel and a strong, continuous flame. The instructions below will help you determine if your furnace is receiving the correct amount of gas and if it is going where it should. To adjust the height of the pilot flame, locate the flame adjustment screw near the gas valve on the pilot assembly. Turn the screw until the flame is 1.5 to 2 inches high. Professional assistance is necessary to adjust the main burner flame height. To detect gas leaks, mix liquid detergent and water and apply it to the gas supply line’s connections and valves. Any leak will cause the soapy water to bubble. If a leak is found, use a pipe wrench to tighten the connection, being careful not to over-tighten. If the connections or valves continue to leak, call a professional service person. For more home repair articles, check out the links provided.
FAQ
1. What are the most common problems with gas furnaces?
Some of the most common problems with gas furnaces include a faulty thermostat, a dirty or clogged filter, a malfunctioning pilot light, a malfunctioning ignition system, a blocked ductwork, and a faulty blower motor. These problems can cause the furnace to not heat up, produce inadequate heat, or turn on and off frequently. It is important to have these issues addressed promptly to prevent further damage to the furnace.
2. How can I troubleshoot my gas furnace?
You can troubleshoot your gas furnace by checking the thermostat settings, replacing the air filter, checking the pilot light and ignition system, checking the ductwork for blockages, and ensuring that the gas supply is turned on. You can also visually inspect the furnace for any signs of damage or wear and tear. However, if you are unsure of how to troubleshoot your furnace, it is best to contact a professional HVAC technician for assistance.
3. How often should I have my gas furnace serviced?
You should have your gas furnace serviced at least once a year by a professional HVAC technician. Regular maintenance can help prevent potential problems and ensure that your furnace is running efficiently. During a maintenance visit, the technician will clean the furnace, inspect all components, and make any necessary repairs or adjustments.
4. Can I repair my gas furnace myself?
It is not recommended that you attempt to repair your gas furnace yourself unless you are a trained HVAC technician. Gas furnaces can be dangerous to work on and can cause serious injury or even death if not handled properly. It is best to leave any repairs to a professional who has the necessary training and experience.
5. How much does it cost to repair a gas furnace?
The cost to repair a gas furnace can vary depending on the extent of the damage and the parts that need to be replaced. On average, you can expect to pay between $150 and $500 for a repair. However, if the furnace is old or has extensive damage, it may be more cost-effective to replace it instead of repairing it.
6. How long do gas furnaces typically last?
Gas furnaces typically last between 15 and 20 years with regular maintenance. However, if the furnace is not properly maintained or has been subjected to excessive wear and tear, it may need to be replaced sooner. It is important to replace an old furnace before it completely breaks down to prevent potential safety hazards and to ensure that your home is heated properly.
Brody is a skilled craftsman and gardening expert. From renovating living spaces to cultivating lush gardens, Brody’s knowledge and passion shine through, inspiring readers to embark on their own home improvement and gardening journeys with confidence.
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