Can a dirty filter stop a furnace from working?

Dirty filters are the most common cause of furnace problems. Dust and dirt restrict airflow—and if the filter gets too clogged, the furnace will overheat and shut off too quickly, and your house won’t warm up. If the blower is running but no heat is coming out, replace the filter. A dirty filter also causes soot buildup on the heat furnace, reducing the efficiency of the furnace and shortening its life. So, if you have the question: “Can a dirty filter stop a furnace from working“, you get the answer.

Here are some steps to fix the furnaces that you can do it yourself.

Solution 1: Check the thermostat to make sure it’s on

The quick fix first that cost little or nothing is check the thermostat. Before you assume you have a furnace problem, do some furnace troubleshooting and check the thermostat to make sure it’s actually telling the furnace to come on. Thermostats, especially programmable ones, can be complicated, and the more options a thermostat has, the more that can go wrong.

  • Make sure the switch is on “Heat” rather than on “Cool.”
  • Check the temperature setting.
  • Compare the temperature setting to the room temperature. Set the temperature five degrees higher than the room temperature and see if the furnace kicks on.
  • Make sure the program is displaying the right day and time, as well as a.m. and p.m. settings.
  • Trace the thermostat wires back to the furnace to check for breaks, especially if you’ve done any remodeling recently. If you find a break in one of the thin wires, splice the line back together and wrap it with electrical tape.
  • Replace the battery. If you have a power outage with a dead battery, you’ll lose your settings and the thermostat will revert to the default program.
  • Open the thermostat and gently blow out any dust or debris. Make sure it’s level and firmly attached on the wall, and that none of the wires coming into it are loose.
  • If you can’t make the program settings work, you can bypass them altogether. Simply punch in the temperature you want with the up/down control and then press the hold button. That will switch on the furnace if the thermostat programming is the problem.

Solution 2: Check shutoff switches and breakers

It sounds unbelievable, but furnace technicians often find that the only ‘repair” a furnace needs is to be turned on. Look for a standard wall switch on or near the furnace—all furnaces, no matter what age or type, have one somewhere. Check the circuit breaker or fuse for the furnace as well. Make sure the front panel covering the blower motor is securely fastened—there’s a push-in switch under it that must be fully depressed for the furnace to operate.

Related post: How to fight dust in your production area.

Solution 3: Change filters

The owner’s manual shows where the filter is and how to remove it. Change inexpensive flat filters at least once a month. Make sure that the arrow points toward the furnace. Inspect pleated filters once a month. Hold them up to the light and if you can’t see the light clearly through them, replace them. Manufacturers say pleated filters are good for three months, but change them more frequently if you have pets, kids or generate lots of dust.

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