Most furnace flame sensors cost less than $20, but if you opt to have a professional HVAC technician make the repair, you can expect to pay between $75 and $250. Need help replacing your flame sensor?
They will cost around $200 if it is done during regular maintenance service. Likewise, flame sensors can become too dusty and malfunction, but a thorough cleaning can restore them. However, if it's too late and you need to replace the flame sensor, expect to pay between $80 and $250.
A heat exchanger replacement is often one of the most costly repairs in a furnace, and the expense can sometimes rival that of installing a new furnace. Typical replacement costs vary widely but can easily reach several thousand dollars, especially if labor costs are factored in.
A flame sensor is a steel rod, not prone to failure, unless there's a build-up on it. Neither part is expensive, and both can be replaced in 20 minutes, assuming it's not hard access.
The sensor's failure to detect a flame causes the furnace to shut down as a safety measure. Inconsistent heating: A faulty flame sensor can cause the furnace to cycle on and off frequently, leading to inconsistent heating in your home. You may notice hot and cold spots or a lack of comfortable warmth.
1. Will a furnace run without a flame sensor? No, a furnace will not operate without a flame sensor.
While most furnaces last for 10 to 20 years, flame sensors have a much shorter lifespan of about five years. Usually, when a flame sensor goes bad, the best route is to replace it outright.
If a flame sensor replacement is necessary, it's a low-cost fix that you can likely handle yourself if you feel comfortable working with the unit.
Do flame sensors wear out? Flame sensors wear over time. However, often the problem is a dirty sensor, rather than a broken one. Since these sensors are designed to have a low tolerance for reading variations, they might misread from the slightest carbon coating.
When the flame lights, you should read between 0.5 and 10 microamps (μA), depending on the furnace. Readings between 2 and 6 are common.
The average cost of an HVAC service call is about $100 to $250, depending on the problem. The total hourly rate for an HVAC technician ranges from $65 to $150+ per hour, with additional parts costing anywhere from $40 to over $1000.
Repair: If your furnace system is less than 15 years old and the cost of repair is less than half the cost of replacement. Replace: If your furnace system is more than 15 years old and requires a costly repair to maintain efficiency.
While there's no such thing as furnace or boiler replacement insurance, homeowners insurance may cover the cost to replace your furnace or boiler if it's damaged or destroyed by a covered peril.
The most expensive, however, is the heat exchanger. The heat exchanger expands and contrasts anytime the furnace fires up. It is made out of metal; over the years, it fatigues, and that's why it's given a twenty-year lifespan.
Flame Sensor Lifespan
Flame sensors have an average lifespan of about five years. Therefore, you can expect to need to replace it at least twice before replacing your entire heating system.
Your Furnace Turns On and then Off Quickly
If your furnace starts up, but then turns off within a few seconds it is short cycling. Short cycling is a common sign of a bad flame sensor.
It's a thin, metal rod that monitors the pilot flame. If the pilot flame goes out, the flame sensor will turn the unit off to prevent natural gas from leaking into the home. 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.
Furnace Short Cycling
Several furnace problems, including a bad flame sensor, can lead to short cycling. If the sensor is dirty or malfunctioning, it might not sense the flame even if it's present. As a result, the furnace will shut down immediately after kicking on.
It is not likely a flame sensor needs to be replaced. You should be able to sufficiently clean a sensor no matter how dirty it is. But they are not expensive parts, and you can choose to replace it instead of cleaning it. There are different shapes of flame sensors so be sure you are purchasing the proper kind.
There is a work-around to waiting. If there is no safety risk (like a gas leak), a furnace can be reset to bypass this wait. Turn off the furnace's power switch and wait 10 seconds before turning it back on.
Flame sensors and thermocouples are both furnace safety components that sense heat and prevent gas leaks. However, the two parts function differently and are not interchangeable. Thermocouples are used in furnaces with pilot lights; flame sensors are used in furnaces with electronic ignitions.
If your furnace keeps turning off and on, your thermostat may be the culprit. A malfunctioning or improperly placed thermostat can cause your furnace to short cycle. Common issues include: Old wiring or dead batteries: Replace batteries or old wiring to ensure accurate temperature readings.
Pilot Lights and Flame Sensors Could Be the Issue
A modern furnace without a pilot light relies on flame detectors to ensure the successful completion of a heating cycle. If the flame detector is covered in dust, dirt, or grime, you will quickly lose heat and your gas furnace will start blowing cold air.