Table of Contents
Turn off electrical power to your furnace either at the furnace or at the electrical box. Close the gas valve. Remove the flame sensor.Cleaning the Flame Sensor Shut off power and gas to the furnace. Remove the sensor. Clean away soot and corrosion with a clean emery cloth. Reinstall the flame sensor. Restart the furnace.
How can I bypass the flame sensor?
We have a different solution: Remove the access cover on the furnace. Locate the flame sensor. Cut the power to the furnace. Shut off the gas control valve. Take out the flame sensor by removing the mounting screw. Examine the part to see if it’s compromised, either by damage or dirtiness.
How do I know if my furnace flame sensor is bad?
First, check for your gas burners to light up and then go out after a few seconds. This is the most common sign of a sensor issue. Second, if you can actual see soot covering the tip of the sensor, it’s time for a cleaning. If you look at the tip and it’s black, it’s time for service.
How do you test a bad flame sensor?
How do I know if my furnace flame sensor is bad? Switch off the power to your furnace. Close the gas valve. Take out the mounting screw. Carefully pull out the sensor. Inspect the sensor: if the insulation is intact but appears sooty, burnt or slightly corroded, it might only require cleaning.
Why is my flame sensor not working?
A flame sensor failure is pretty common due to buildup of materials and particles in the confined area of the furnace. To clean the flame sensor, start by making sure your furnace is off—it can be turned off using the switch on the unit or by cutting the power source at the breaker box.
How does the flame sensor on a furnace work?
A furnace flame sensor works by detecting the presence of a flame within the furnace. As the gas valve opens to begin the combustion process, the current is sent out from the sensor in order to detect the presence of heat from a flame.
Why do furnace flame sensors go bad?
What Causes a Flame Sensor to Get Dirty? It’s possible for a flame sensor to go bad; but more often than not, it is not broken, just dirty from carbon buildup. Because a flame sensor has a very low tolerance for variations in the reading it takes, the slightest coating of carbon can cause it to misread and shut down.
How often do furnace flame sensors go bad?
Flame sensor lifespan If you’ve just replaced the sensor or had a new furnace installed, you can expect the flame sensor to last for about five years. The average lifespan of a furnace is 15 to 30 years, so you can anticipate a flame sensor replacement once or twice over the course of your homeownership.
Can you Ohm a flame sensor?
Follow these steps to test the flame sensor: You can do this by powering down the furnace and taking an ohm reading between neutral and the burner assembly/manifold. You should read a few ohms of resistance max, the lower the ohm reading the better grounded it is.
Are all flame sensors the same?
Not all furnaces have a flame sensor, but if your furnace has one, it will be mounted close to the burner with the metal rod positioned in the flame. Flame sensors vary in size (2 to 4 inches) and shape (see examples below).
How much is a flame sensor for furnace?
Flame Sensor If the sensor is bad, it won’t be able to sense heat and will turn the furnace off. The average cost to repair or replace a flame sensor is between $75–$200.
Does a flame sensor need to be grounded?
A flame sensing rod is a piece of metal with a ceramic insulator that keeps it from grounding out. That is all. However, because it is conducting in the millionths of an amp (microamp), a lot can go wrong with it that a normal electrical component wouldn’t have any issue with.
What causes a gas furnace not to ignite?
Common types of natural gas issues include gas leaks, blocked gas lines, and malfunctioning gas valves. If the gas line is off, simply turn it back on. If the furnace won’t ignite after doing this, call an HVAC professional to check for other potential problems.
Are flame sensors universal?
Universal flame sensors: You might not need an exact replacement part. Universal sensors are available too. They are available at Home Depot, Menards or other building supply store.
How do you fix flame sensed out of sequence?
4 Flame sensed out of sequence If situation self corrects within 10 seconds, control module returns to normal sequence. If flame out of sequence remains longer than 10 seconds, control will resume normal operation 1 hour after error is corrected. Check for pilot flame. Replace gas valve if pilot flame present.
Why do we need flame sensor?
A flame sensor is a crucial safety component on your gas heating system. During the ignition cycle, your gas furnace goes through a process where a spark or a hot surface ignitor will actually ignite the gas. As the gas is ignited, the flame sensor creates a current of electricity.
