Can a flame sensor go bad?

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.

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In this way, how do you know if a flame sensor is bad?

Signs of a bad furnace flame sensor are:

1. The furnace lights but then shuts down after a few seconds (short cycles)
2. The porcelain on the flame sensor is cracked.
3. The flame sensor is sooty or corroded.

Also, what causes a flame sensor to go bad? As with any piece of equipment a simple reason could be that dirty flame sensor just goes bad. However a more common reason is that it is just dirty. It is a sensitive sensor so any type of dust or carbon buildup could cause it to malfunction.

Then, do flame sensors wear out?

If no flame is present, the sensor stops or prevents the flow of gas from the gas valve, thus preventing the dangerous situation of gas flowing into the appliance when there is no flame to burn it. Flame sensors and thermocouples are simple parts that wear out and fail over time, and most are easy to replace.

When should I replace my flame sensor?

If the furnace ignition control is seeing a flame current that is within the ignition control's normal range, there is no reason to change the flame sensor unless the flame sensor has a burnt look or it is pitted. If the flame sensor has a normal look, you can just clean it.

Related Question Answers

How much does it cost to replace a flame sensor?

Repairing a furnace igniter will only cost you $300 at most, while flame sensor repairs generally fall between $80 to $250. The average cost to repair your Thermostat will range from $108 to $282.

How long do flame sensors last?

Most of the time it is the flame sensor. Problem: Your furnace main burner ignites, the main burner stays on for 8 to 10 seconds, then shuts right back off.

How do you test a flame detector?

1. Point at the flame detector within the test distance within the vision of detector.
2. Press the trigger and wait until the Flame detector is activated.
3. Verify that the switch at the back of test lamp is in the continuous mode.
4. Operate the test lamp for at least the selected delay time of the detector.

What should a flame sensor read?

When the flame lights you should read between . 5 and 10 microamps (μA) depending on the furnace. Readings between 2 and 6 are common.

Why does my furnace flame keeps going out?

Your furnace has a limit switch that keeps it from running if the heat exchanger is too hot. Dirty filters, closed or blocked vents and other blockages in airflow are common causes of an overheated furnace. A direct ignition furnace has flame sensor over the burner that shut off the gas if it doesn't sense a flame.

Can you clean a furnace ignitor?

Clean the dust off the hot surface igniter by leaving the igniter in place and blowing air through a straw. This part breaks very easily; don't even touch it. In fact, when you replace the furnace doors, do so gently to avoid breaking the igniter.

What does a flame sensor look like?

A furnace flame sensor is a very basic part of your furnace. It's located on the burner assembly and is just a thin metallic rod. It's usually bent, and it sits just in front of the pilot flame inside the furnace. The sensor is there to confirm that there's actually a fire present when the gas is open.

Can you clean a flame sensor rod?

Clean the Sensor. Once you have removed the sensor, gently rub the metal rod (only) with soft steel wool or soft scotch brie type pad NEVER USE SANDPAPER as it will damage the flame rod. Then, use a clean paper towel to wipe clean any dust left behind .

How does the flame sensor work?

A furnace flame sensor works by detecting the presence of a flame within the furnace. The sensor is a short length of thin metallic rod that creates a small current of electricity in order to confirm there is fire burning within the furnace.

Can hear your furnace click on but it does not fire up?

The Pilot Light (Faulty Ignition Sensor) The pilot light or ignition sensor is usually the most common issue when your furnace will not ignite. This is typically the problem if you can hear your furnace click on but it does not fire up. If the sensor or ignitor is dirty, it will need to be cleaned.

Does Home Depot sell flame sensors?

Flame Sensor for Hot Surface Ignition-760-401 - The Home Depot.

What is a flame sensor made of?

The safety used in today's furnaces that accomplishes flame rectification is the flame sensor. A flame sensor is nothing more than a stainless steel rod partially encased in porcelain.

What is flame rollout switch?

The rollout switches are placed as a safety device around the burner area to sense the hot flame or hot exhaust thus shutting down the furnace so you do not get a fire or get carbon monoxide poisioning. The push button manual set rollout switch is located in the middle.

Do all 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).

Why is my furnace not igniting?

If the furnace doesn't ignite when the thermostat calls for heat, it may be due to a faulty control module, faulty pilot burner, damaged spark electrode or loose connections to the control module. The hot surface ignition system uses an electronic heating element to ignite the gas burner.

How do you clean a thermocouple?

Remove Thermocouple from pilot assembly, using steel wool or emery cloth to lightly clean the tip removing any soot or build up that might have accorded due to an improper pilot flame. Using an eraser from a pencil; clean the threads of the nut that connects the Thermocouple to the control valve and then re-tighten.

How long does furnace ignitor last?

four to seven years

How do you clean the flame sensor on a Lennox furnace?

How to Find & Clean a Flame Sensor in a Lennox Furnace

1. Flip the circuit breaker switch that corresponds to your Lennox furnace to the "Off" position.
2. Lift the access panel on the front of the furnace straight up to clear the tabs on the bottom of the furnace cabinet.
3. Look for a thin metal rod on the left side of the burner assembly; this is the flame sensor.

How do you clean the flame sensor on a Rheem furnace?

How to Clean the Flame Sensor on Rheem Heaters

1. Turn off the power supply to your heater at the breaker box.
2. Remove the lower front panel from the heater to access the burners.
3. Pull out the flame sensor once you locate it.
4. Wipe the surface of the flame sensor down with 400-grit sandpaper.
5. Reinstall the flame sensor reversing the steps you took to remove it.