How To Check the Flame Sensor on a Furnace

If your furnace isn't heating properly, you need experts on your side. Contact Bates Air & Heat LLC for high-quality and affordable HVAC services. 

Modern gas furnaces can't produce heat if there is no flame near the burner. Along with the burner, one of the most important parts of a furnace is the flame sensor, which regulates the temperature of the heat cycle so the system doesn't overheat. Learn how to check flame sensors on a furnace so you can pinpoint potential problems with your unit. 

Contact Bates Air & Heat LLC, the most trusted HVAC company in Vero Beach, if you need professional heating repairs, maintenance, or installation. Our friendly experts can identify issues with your heating system, like a broken flame sensor, and quickly resolve any problems that arise. 

What Is a Furnace Flame Sensor?

If you're going to conduct a furnace flame sensor inspection, it's important to first understand this vital piece of the heating system. What is a furnace flame sensor? This aptly named part detects the spark that triggers the rest of the heating system. 

Its primary purpose is to make sure that the flame heating the burner doesn't get too hot. When this happens, the furnace will automatically shut off to prevent dangerous malfunctions. Homeowners should know how to check the flame sensor on a furnace because any trace of dirt or debris can impact its function and put the household at risk for fire hazards and unreliable heating. 

Signs You Have a Faulty Flame Sensor

How can you tell when flame sensor troubleshooting is necessary? You'll likely find that your furnace starts having problems with its performance, impacting your home's comfort level. Keep an eye out for the following warning signs that indicate you have a faulty flame sensor.

Your Furnace Short Cycles

Typically, a furnace's heat cycle will last about 15 minutes. If the cycle is cut short and only lasts a minute, it's possible that your flame sensor isn't able to detect the flame. A thick layer of dirt or smoke could cover the sensor and prevent it from identifying the pilot light. 

The sensor could be malfunctioning even if it's clean. The safety trigger may shut off the system when the temperature is safe because of a glitch. 

Your Energy Bills Increase

Any time that your heating costs skyrocket without explanation, it's a sign that something is wrong with your HVAC system. You'll need to know how to check the flame sensor on a furnace if your utility bills drastically increase despite no change in your heating habits. Your inspection could end up saving you money and making your furnace more energy efficient. 

How To Perform a DIY Flame Sensor Check

When it comes to checking furnace flame sensors, homeowners can inspect the equipment without calling a professional. Doing this yourself presents some safety concerns, so make sure you follow the steps below to avoid putting yourself in harm's way. 

Turn Off the Heater's Power and Fuel Source

If you're wondering how to check the flame sensor on a furnace, the most important step is remembering to turn off the gas and electricity supply to your furnace. Tinkering with your furnace while it's still receiving gas and electricity poses significant safety risks. Cut off the power supply and wait a few minutes for the gas to dissipate before moving ahead. 

Locate and Remove the Sensor

Once you shut off the gas and electric power to your furnace, you'll need to locate the flame sensor. This part resembles a thin metal rod along the interior of your furnace where the pilot light usually blazes. Disassemble it so you can test its function. 

Test the Sensor Using a Multimeter

You can test your furnace's flame sensor using a tool called a multimeter, which measures electric currents within items. Set the multimeter so measurements appear in micro-amps. Then, connect one of the instrument's wires to the flame rod and the other to the furnace where the flame sensor normally goes. 

Turn on the unit after you attach the wires in their proper places. Your multimeter should have a reading between .5 and 10 micro-amps, though falling between two and six micro-amps is the normal range. If the test doesn't produce a normal reading, it's time to try cleaning off the flame sensor. 

Clean the Flame Sensor

After completing the flame sensor testing procedure, you may have to clean off the rod. Experts recommend waiting for the rod to cool down and gently scrubbing it with a piece of sandpaper or steel wool. Using too much force while cleaning it could damage the rod, so be careful not to scrape too hard. 

Importance of Furnace Sensor Maintenance

Knowing how to check the flame sensor on a furnace can help you avoid major malfunctions that require costly repairs. Testing the sensor when you start experiencing issues with your heater is smart; however, experts recommend conducting regular maintenance. 

Failing to check the flame sensor and other essential parts of the system can damage the furnace beyond repair. You'll likely end up paying higher energy bills and the cost of replacing your furnace. Scheduling annual furnace maintenance helps you save money and keeps all of the components working properly. 

Professional technicians will inspect all parts of the furnace, including:

• Flame sensor
• Heat exchanger
• Blower fan
• Pilot light
• Gas valves
• Electrical wiring

They'll clean any dirt and debris from internal components so the system runs more efficiently. 

Contact Bates Air & Heat LLC for Superior Heating Repairs and Services

Any number of issues can impact your furnace's function. If you're not sure how to check the flame sensor on a furnace or what to do when the furnace pressure switch goes bad, turn to the specialists at Bates Air & Heat LLC. We offer high-quality heating repairs and replacement services to homeowners across Florida's Southeastern coast. 

Reach out to our friendly technicians whenever you need professional HVAC solutions. Call (772) 837-5109 to request immediate service.