Lennox 10F74 Contactor

As a field-tested Lennox 10F74 contactor, this definite purpose contactor is the industry-standard solution for maintaining the structural integrity of residential air conditioning and heat pump systems. Engineered as a 1-pole contactor with a 24V coil, this high-amperage component is rated for 40 FLA (Full Load Amps) and 200 LRA (Locked Rotor Amps) at 240V. Whether you are performing a routine service call or emergency equipment restoration, this OEM replacement part ensures seamless integration with existing control wiring, effectively preventing pitted contacts and premature compressor failure.

The Lennox 10F74 is designed to replace aging or 13-year-old control relays in high-ambient environments. It features a compact footprint (approximately 2" x 2.5" x 3.26") to fit within tight electrical compartments in popular units like the XC17 and XP20 series. This SPST N.O. (Single Pole Single Throw, Normally Open) switch comes equipped with a shunt to maintain power to the crankcase heater even when the contactor is disengaged, ensuring the system is ready for the next cooling cycle without refrigerant migration issues. This part is the verified direct replacement for legacy catalog numbers including 10F7401, 95M56, 95M5601, and 65C70.

• Heavy-Duty 40 Amp Rating: Built to handle higher inductive loads, reducing the risk of contact welding during peak summer demand.
• Direct OEM Compatibility: Eliminates the need for field modifications, fitting perfectly into Lennox, Armstrong, and Ducane equipment.
• Silver Cadmium Oxide Contacts: Engineered for long-term conductivity and resistance to electrical arcing.
• Universal 24VAC Control: Compatible with all standard 24-volt transformer outputs and digital thermostats.

Is the 10F74 compatible with my 2-pole system?
This is a 1-pole contactor with a shunt. If your original part has two physical poles that break both lines of power, you should verify if your local code or specific unit requires a 2-pole replacement. For most Lennox residential split systems, this 1-pole design is the factory-specified configuration.

What are the symptoms of a failing Lennox contactor?
Technicians typically look for chattering sounds, "pitting" on the contact surfaces, or a burnt coil smell. If the 24V signal is present but the compressor fails to engage, the 10F74 is the primary component to test for continuity.

Can I use this to replace a 30 amp contactor?
Yes, upgrading from a 30 amp to a 40 amp contactor is a common best practice among veteran HVACR contractors as it provides a higher safety margin and better heat dissipation under heavy loads.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.