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Luckily, making such a check is very easy: Take a multimeter with microamps (µA) measuring system. Keep the furnace system turned on. Connect it to the wire that is leading to the gas valve. Connect the other side of the multimeter to the sensor terminal. Take the lead away from the flame sensor.
How do I bypass flame sensor temporarily?
The process is rather simple: 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.
Can a furnace run without a flame sensor?
The flame sensor is an important safety feature inside a furnace. Without the flame sensor, if the pilot light goes out but the gas valve remains open, the gas will not burn and will seep out of the furnace. This is a dangerous situation that can result in gas poisoning or even an explosion.
How does a flame sensor 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.
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.
Why do I have to keep cleaning my flame sensor?
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.
Can you bend a universal flame sensor?
The Robertshaw® Flame Sensor Assembly and Replacement Sensors have high temperature Kanthol sensor rods that will withstand 1800°F (982°C). The sensor rod is 4” long and can be cut and bent to match an original unit.
Is a thermocouple the same as a flame sensor?
People tend to use the terms “flame sensor” and “thermocouple” interchangeably. In truth, while they basically perform the same job, they’re not the same thing. If your furnace uses an electronic controller, it’s got a flame sensor. Thermocouples are used on standing pilot furnaces that have pilot lights.
How much does flame sensor cost?
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.
How long do flame sensors last?
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.
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.
How many volts should a flame sensor read?
Now we want to check flame sensor voltage. If the voltage is not within range there will not be enough electrical pressure to push the current through the flame. With your voltmeter, check the voltage between the sensor wire and the burner – it should be 90-107 volts AC.
Can a flame rod be cut?
Heating Sensors Series The Robertshaw® Flame Sensor Assembly and Replacement Sensors have high temperature Kanthol sensor rods that will withstand 1800°F (982°C). The sensor rod is 4” long and can be cut and bent to match an original unit. Excellent replacement for most manufacturers’ flame sensors.
How do you fix a yellow flame on a gas heater?
Gas burners burn blue if the ratio of fuel to air is correct. A yellow burner flame is a symptom that the burner is not getting enough air for complete combustion of the gas. Correcting this problem involves adjusting the burner’s air shutter to admit more air, something that an experienced do-it-yourselfer can do.
Can you use sandpaper to clean flame sensor?
To clean the sensor, simply rub the metal rod gently with light grit sandpaper, steel wool, or emery cloth to eliminate the carbon buildup. Note: Never use sandpaper as it will damage your flame sensor’s rod. After that, use a clean and dry paper towel to get the excess particles and dust from the metal rod.
How do flame sensors get dirty?
It is a sensitive sensor so any type of dust or carbon buildup could cause it to malfunction. Most people have their furnaces in a basement or laundry area where there is excess dust in the air. This dust could stick to the sensor making it dirty and causing your furnace to shut down.
How often does a flame sensor need to be replaced?
Note: According to HVAC.com, the expected lifespan of a flame sensor is about 5 years. Most furnaces last anywhere from 10 to 20 years. That means that you will have to replace a flame sensor 1x, 2x, or even 3x during a furnace’s lifespan.
Do all gas furnaces have a flame sensor?
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).
Do electric furnaces have flame sensors?
Electric furnaces work differently from gas and propane furnaces. They do not have a flame sensor as they don’t use a flame to heat your home. A flame sensor automatically turns off your gas furnace if it detects that there isn’t a blue flame lit when the gas valve is open.
