Watching Those Filters

How To Troubleshoot A Forced Air Furnace

If your forced air system isn't working properly, it is possible to troubleshoot the problem. As the name implies, a forced air heat system warms colder air through a heat exchanger, then a fan passes the warmed air into the room. Several issues can occur with a forced air system, so it needs regular maintenance.. Here are tips to troubleshoot a forced air heat system.

Low Heat or No Heat: Check the Thermostat or Pilot

For this project, you need compressed air, a screwdriver, and duct tape. When the furnace runs, but produces low heat or no heat, it is often an issue with the thermostat or pilot. Ensure the thermostat is on "HEAT" mode, and raise the temperature three degrees.

If this doesn't help, use the screwdriver to remove the panel, and check for dirt. Spray some compressed air on the coils. Look for loose wiring while you have the panel open. To fix loose wiring, turn off the power and tighten the connection. 

If the display fails to light, or looks weak, change the batteries. Verify that the emergency switch is turned "On." The emergency switch resembles a light switch, and it is commonly near or on the furnace. 

Check the pilot on a gas furnace to verify it is still lit. Follow the instructions in your manual to relight it if it has gone out. 

No Power: Inspect Breakers and Reset Button

Sometimes, a tripped breaker can cause the furnace not to operate. Look inside your breaker box, and inspect it for tripped breakers. A tripped breaker often moves to the middle or the opposite end of where it originally rests. Flip it back in place, and try the furnace again. If it keeps tripping the breaker, the system could be shorted.

Sometimes, the red reset button on furnaces pops out, causing the system to not start. Inspect the reset button and reset it. 

Fix Short Cycling

Short cycling means the heating unit turns on and off frequently, which could be because of dirty air filters or the actuator. Locate the actuator, which is a thin, pointy dial inside the thermostat. If the dial is set to 2 or lower, raise to 3 or 4 to help stop the short cycling..

Shut off the power or gas to the unit. Use a screwdriver to remove the furnace access panel screws, and set the parts aside. Look for the filters near the outtake/intake blower, and check them for dirt or damage. Wash them with a cloth dampened in cool water, then let them dry. Replace damaged filters, and reinstall the access panel.

You save money by doing your own troubleshooting and repair. If you don't trust your skill, or the furnace still doesn't work, contact a HVAC service like HELP Plumbing, Heating, Cooling and Electric.