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Furnace & HVAC Sensors

Furnace & HVAC Sensors

Shop furnace and HVAC replacement sensors for residential, commercial, and industrial heating and cooling systems. Furnace Part Source carries temperature sensors, immersion sensors, humidity sensors, flow sensors, and safety probes from Honeywell, Siemens, Veris Industries, MAMAC Systems, System Sensor, and other leading brands.

Use the product list below to find the correct sensor by part number, sensor type, or equipment model. Always confirm resistance value, output signal, mounting style, and equipment model before ordering to help avoid compatibility issues.

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    Lennox 52M72 Flame Sensor

    Lennox

    MSRP: $35.23
    Now: $27.22
    Flame Sensor  FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - EverytimeNo Minimum Order Requirements
    MSRP: $35.23
    Now: $27.22
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    MSRP: $35.23
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    Lennox 49M84 Flame Sensor

    Lennox

    MSRP: $24.67
    Now: $19.06
    Lennox 49M84  Flame Sensor   FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - Everytime No Minimum Order Requirements    
    MSRP: $24.67
    Now: $19.06
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    Lennox 49K08 Temperature Sensor,12" Probe

    Lennox

    MSRP: $13.15
    Now: $10.16
    Lennox 49K08  Temperature Sensor,12" Probe   FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - Everytime No Minimum Order...
    MSRP: $13.15
    Now: $10.16
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    Lennox 48G63 SUPPLY Air Sensor

    Lennox

    MSRP: $93.54
    Now: $72.28
    SUPPLY Air Sensor  FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - EverytimeNo Minimum Order Requirements
    MSRP: $93.54
    Now: $72.28
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    MSRP: $93.54
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    Lennox 47W36 Averaging Space Sensor

    Lennox

    MSRP: $114.87
    Now: $88.77
    Averaging Space Sensor  FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - EverytimeNo Minimum Order Requirements
    MSRP: $114.87
    Now: $88.77
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    MSRP: $114.87
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    Lennox 47K19 Defrost Sensor

    Lennox

    MSRP: $34.98
    Now: $27.03
    Defrost Sensor  FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - EverytimeNo Minimum Order Requirements
    MSRP: $34.98
    Now: $27.03
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    MSRP: $34.98
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    Lennox 32M86 Flame Sensor

    Lennox

    MSRP: $5.87
    Now: $4.54
    Flame Sensor   FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - Everytime No Minimum Order Requirements    
    MSRP: $5.87
    Now: $4.54
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    MSRP: $5.87
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    Lennox 28W70 Wire Harness W/Defrost Sensor

    Lennox

    MSRP: $113.02
    Now: $87.34
    Wire Harness W/Defrost Sensor   FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - Everytime No Minimum Order Requirements    
    MSRP: $113.02
    Now: $87.34
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    MSRP: $113.02
    Now: $87.34
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    Lennox 27J02 Flame Sensor

    Lennox

    MSRP: $34.29
    Now: $26.49
    Flame Sensor   FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - Everytime No Minimum Order Requirements    
    MSRP: $34.29
    Now: $26.49
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    MSRP: $34.29
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    Lennox 26G10 Defrost Sensor L70-35F

    Lennox

    MSRP: $45.26
    Now: $34.97
    Lennox 26G10  Defrost Sensor L70-35F   FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - Everytime No Minimum Order...
    MSRP: $45.26
    Now: $34.97
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    MSRP: $45.26
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    Lennox 21L99 Flame Sensor

    Lennox

    MSRP: $24.67
    Now: $19.06
    Lennox 21L99 Flame Sensor   FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - Everytime No Minimum Order Requirements    
    MSRP: $24.67
    Now: $19.06
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    MSRP: $24.67
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    Lennox 17M50 Humidity Sensor

    Lennox

    MSRP: $453.22
    Now: $350.22
    Humidity Sensor   FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - Everytime No Minimum Order Requirements    
    MSRP: $453.22
    Now: $350.22
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    MSRP: $453.22
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    Lennox 17J56 Flame Sensor

    Lennox

    MSRP: $23.50
    Now: $18.16
    Flame Sensor   FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - Everytime No Minimum Order Requirements    
    MSRP: $23.50
    Now: $18.16
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    MSRP: $23.50
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    Lennox 14K92 OutdoorTemperature Sensor

    Lennox

    MSRP: $31.25
    Now: $24.15
    OutdoorTemperature Sensor  FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - EverytimeNo Minimum Order Requirements
    MSRP: $31.25
    Now: $24.15
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    MSRP: $31.25
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    Lennox 14B53 Ambient Temperature Sensor

    Lennox

    MSRP: $74.68
    Now: $56.58
    Ambient Temperature Sensor  FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - EverytimeNo Minimum Order Requirements
    MSRP: $74.68
    Now: $56.58
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    MSRP: $74.68
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    Lennox 13H27 Electrode/Sensor

    Lennox

    MSRP: $47.70
    Now: $36.86
    Electrode/Sensor  FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - EverytimeNo Minimum Order Requirements
    MSRP: $47.70
    Now: $36.86
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    MSRP: $47.70
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    Lennox 11M65 Flame Sensor LEAD

    Lennox

    MSRP: $26.61
    Now: $20.57
    Flame Sensor LEAD   FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - Everytime No Minimum Order Requirements    
    MSRP: $26.61
    Now: $20.57
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    MSRP: $26.61
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    Carrier TSTATXXSEN01B Outdoor Temperature Sensor

    Carrier

    MSRP: $43.08
    Now: $33.29
    Outdoor Temperature Sensor   FurnacePartSource.com Commitment Item Typically Ships within the Same Business Day Brand-New Genuine Parts - Everytime No Minimum Order Requirements    
    MSRP: $43.08
    Now: $33.29
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    MSRP: $43.08
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    Carrier SYSTXCCRRS01 Infinity Remote Room Temperature Sensor

    Carrier

    MSRP: $118.65
    Now: $91.69
    Carrier SYSTXCCRRS01  Infinity Remote Room Temperature Sensor Item is Non Cancelable / Non Returnable FurnacePartSource.com Commitment Item Typically Ships within the Same Business...
    MSRP: $118.65
    Now: $91.69
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    MSRP: $118.65
    Now: $91.69
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    Carrier LH33WZ520 Flame Sensor

    Carrier

    MSRP: $25.94
    Now: $20.04
    Flame Sensor   FurnacePartSource.com Commitment Item Typically Ships Within the Same Business Day Brand-New Genuine Parts - EverytimeNo Minimum Order Requirements
    MSRP: $25.94
    Now: $20.04
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    MSRP: $25.94
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Furnace & HVAC Sensors

Furnace and HVAC sensors monitor temperature, airflow, flame presence, humidity, and other conditions that keep a heating or cooling system operating safely and efficiently. When a sensor fails or reads inaccurately, it can cause lockouts, poor comfort control, or unsafe operation.

Furnace Part Source carries a wide range of replacement sensors, including duct and immersion temperature sensors, outside air sensors, humidity sensors, flow sensors, and safety-related probes for residential, commercial, and industrial HVAC equipment.

Common Sensors We Carry

Common replacement sensors include:

  • Duct and immersion temperature sensors for supply, return, and water temperature readings.
  • Outside air temperature and humidity sensors for outdoor reset and economizer control.
  • Flow sensors for airflow and duct pressure monitoring.
  • Low-level and safety probe sensors for boiler and water-level protection.
  • Gas and smoke detection sensors for combustible gas and safety monitoring.

How to Find the Right Sensor

Before ordering, confirm the sensor's resistance value (such as 10K or 20K ohm), output signal type, mounting style, and the equipment model it is used with. Sensors that look similar can have different resistance curves or output signals, so matching by part number is the safest approach.

For best fit, compare:

  • Original sensor part number
  • Resistance value or output signal type
  • Sensor style, such as duct, immersion, outside air, or surface-mount
  • Equipment model and control system

Sensors From Leading HVAC Brands

Our catalog includes sensors from Honeywell, Siemens Building Technology, Veris Industries, MAMAC Systems, System Sensor, Dwyer Instruments, Aaon, Kele, and other major manufacturers, covering both standard replacement sensors and specialized industrial sensing equipment.

Need Help Matching a Sensor?

Not sure which sensor you need? Use the part number, resistance value, and control system information from your equipment to narrow the search, or contact Furnace Part Source for help identifying the correct replacement.

HVAC Sensor FAQs

What types of sensors does an HVAC system use?

HVAC systems commonly use temperature sensors, humidity sensors, flow sensors, flame sensors, and safety probes to monitor conditions and support proper system control.

How do I know what resistance value my sensor needs?

Check the original sensor's part number or the equipment documentation, which typically lists the resistance value, such as 10K or 20K ohm, required for compatibility.

Can a bad sensor cause my system to shut down?

Yes. A failed or inaccurate sensor reading can trigger lockouts or prevent proper operation, particularly for safety-related sensors like low-water or flame sensors.

Are furnace sensors and thermostat sensors the same?

No. Furnace and HVAC sensors typically monitor internal equipment conditions, while thermostat sensors read room temperature for comfort control. Always confirm the specific application before ordering.