House Parts [Lifetime Warranty] L210-20F Furnace Primary Limit Switch (-40°F to 180°F) - Compatible with ICP Heil Tempstar Furnaces GDE050B12A2 GDE050B12G1 GDE075F16A3
L210-20F furnace primary limit switch with metal mounting flange and two electrical terminals.
L210-20F furnace primary limit switch showing dimensions and technical specifications.
L210-20F furnace primary limit switch with temperature rating of -40°F to 180°F shown on promotional graphic.
Close-up detail views of the L210-20F furnace primary limit switch showing aluminum and thermoplastic construction.
L210-20F furnace primary limit switch compatibility chart showing two angles of the replacement part.
Compatibility chart for L210-20F furnace primary limit switch listing compatible ICP, Heil, and Tempstar furnace models.
L210-20F furnace primary limit switch shown with technician repairing furnace and list of common repair symptoms.
Four-step installation guide for L210-20F furnace primary limit switch showing removal, testing, and replacement.
L210-20F furnace primary limit switch with metal mounting flange and electrical terminals.
L210-20F furnace primary limit switch with metal mounting flange and two electrical terminals.
L210-20F furnace primary limit switch showing dimensions and technical specifications.
L210-20F furnace primary limit switch with temperature rating of -40°F to 180°F shown on promotional graphic.
Close-up detail views of the L210-20F furnace primary limit switch showing aluminum and thermoplastic construction.
L210-20F furnace primary limit switch compatibility chart showing two angles of the replacement part.
Compatibility chart for L210-20F furnace primary limit switch listing compatible ICP, Heil, and Tempstar furnace models.
L210-20F furnace primary limit switch shown with technician repairing furnace and list of common repair symptoms.
Four-step installation guide for L210-20F furnace primary limit switch showing removal, testing, and replacement.
L210-20F furnace primary limit switch with metal mounting flange and electrical terminals.
Lifetime Warranty

[Lifetime Warranty] L210-20F Furnace Primary Limit Switch (-40°F to 180°F) - Compatible with ICP Heil Tempstar Furnaces GDE050B12A2 GDE050B12G1 GDE075F16A3

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L210-20F Primary Furnace Limit Switch

Key Features

  • Critical safety switch designed to shut down the gas valve and burner circuit if the furnace heat exchanger exceeds maximum safe operating temperatures.
  • Thermal setting calibrated to automatically open the circuit on temperature rise at 210°F and close (reset) at 190°F.
  • Constructed with a highly responsive bimetallic disc enclosed in a temperature-resistant phenolic housing to prevent heat distortion.
  • Features a flush-mount bracket and standard 1/4-inch male quick-connect spade terminals for immediate electrical integration.

Replaces / Cross-Reference Part Numbers

  • L210-20F
  • 34335001
  • 34335-001
  • HQ34335001TD
  • 313408
  • 338085-758
  • 47-25349-06

Compatibility & Fitment

  • Compatible with select residential gas furnaces manufactured by International Comfort Products (ICP), Heil, and Tempstar.
  • Fits specific furnace models including: GDE050B12A2, GDE050B12G1, and GDE075F16A3.

When to Replace

  • The furnace continuously short-cycles, shutting off the burner assembly well before reaching the target thermostat temperature.
  • The furnace blower fan runs non-stop blowing cold air, indicating the system is locked out due to an open limit circuit.
  • The main control board diagnostic LED continuously flashes an error code specifically for an open high-limit switch.
  • A continuity test performed with a digital multimeter displays infinite resistance (an open circuit) while the switch is resting at room temperature.

Installation Tips

  • Turn off the main electrical breaker to the furnace and ensure the unit is completely powered down before opening the service panels.
  • Take a digital photograph of the existing wire connections to ensure the leads are routed back to the correct spade terminals.
  • Remove the two hex screws securing the original switch to the heat exchanger bulkhead and carefully pull the component straight out.
  • Align the new limit switch flush against the mounting surface and tighten the screws down evenly to prevent bending the mounting plate.
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  • WIDE COMPATIBILITY

    WIDE COMPATIBILITY

    Compatible with many models of ICP, Heil, Tempstar Furnaces. Replaces part numbers: HQ34335001TD 338085-758 34335001 313408 34335-001
  • DURABLE MATERIAL

    DURABLE MATERIAL

    This part is made of high-quality aluminum alloy and thermoplastic materials for superior conductivity and high reliability.
  • SAVING SOLUTION

    SAVING SOLUTION

    Enjoy the great feeling when your furnace is repaired and works properly like before - BlueStars brings DIY solution to help you deal with any trouble
  • IMPORTANT NOTE

    IMPORTANT NOTE

    This is a replacement part designed to be compatible with certain appliances. Any brand names mentioned are used solely to indicate compatibility.
CONNECTING LIVES, ENERGIZING MOMENTS

CONNECTING LIVES, ENERGIZING MOMENTS

FAQ

This switch is commonly associated with several furnace brands depending on the specific part number and mounting style. Confirm fit by matching both the L210-20F rating and your original part number. Reported compatible brand groups include Nordyne, Intertherm, Miller, and Tappan, as well as ICP, Heil, Tempstar, Carrier, Day & Night, Keeprite, Comfortmaker, Arcoaire, and Sears.
Known cross-reference numbers for this switch family include 626425, 313408, 34335001, 34335-001, HQ34335001TD, and 338085-758. Always verify the temperature rating, terminal layout, probe length, and mounting style against your original switch before ordering.
L210-20F indicates the switch opens on temperature rise at 210°F. The “-20F” portion refers to the differential, meaning the switch typically resets after the temperature drops by about 20°F. This type of primary limit switch is a safety device that helps shut off the burner if the furnace overheats.
Common symptoms include the burners shutting off before the heating cycle finishes, the blower running excessively, the furnace starting and stopping repeatedly, lockout codes related to open limit, or no heat after an overheating event. Keep in mind that a limit switch may be reacting normally to an airflow or venting problem, so the switch itself is not always the root cause.
Repeated trips are often caused by overheating from restricted airflow rather than a defective switch. Common causes include a clogged air filter, dirty evaporator coil, blocked supply or return vents, blower wheel buildup, weak blower motor performance, or improper gas input. A limit switch can also weaken over time after repeated heat cycles, but it is important to correct the overheating condition before replacing it.
Replacement is usually straightforward for someone familiar with furnace service. Typical steps are shutting off power, removing the access panel, labeling and disconnecting the wires, removing the mounting screws, swapping the switch, and reinstalling the wires. Basic tools are usually a screwdriver and possibly a nut driver. The job often takes about 15 to 30 minutes, but exact access depends on the furnace design.
Before installation, compare the original switch carefully for the same temperature rating, terminal configuration, insertion length, and mounting dimensions. Also inspect the furnace for the reason the old switch opened: check the air filter, blower operation, duct restrictions, indoor coil cleanliness, and venting path. Replacing the switch without fixing an overheating problem can lead to repeat shutdowns.