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White-Rodgers furnace control board with green circuit board and multiple connectors

Emerson Climate Technologies

Emerson Climate Technologies 50A66-743 Integrated Hot Surface Control

SKU CH-4WCM-C9R48

Replaces Lennox furnace boards with a single-stage integrated control that manages gas valves, blowers, ignitors, inducers, humidifiers and air cleaners at 120 V with a 45-second heat blower delay

  • Integrated control manages air cleaners, blowers, gas valves, humidifiers, ignitors and inducers
  • OEM replacement matches Lennox part numbers 100925-01, 100925-02, 100925-03 and White-Rodgers 50A66-122, 50A66-123
  • 120 V control voltage with 25 V AC input powers single-stage furnace systems
  • 45-second heat blower on-delay protects heat exchanger during startup
  • White-Rodgers 50A66-743 model ensures direct-fit compatibility for Lennox equipment

Furnace Control Board

The Emerson Climate Technologies 50A66-743 is an integrated furnace control board designed as an OEM replacement for Lennox systems. It manages ignition, blower operation, gas valve control and connections for air cleaners and humidifiers in residential heating equipment.

Electrical Ratings

The board operates on a 120 V control voltage with a 25 V AC input and provides a fixed 45 second heat blower on delay. It is a single-stage control that coordinates ignitors, inducers and gas valves without variable-speed or modulating functions.

Sustained Operation

Under continuous heating cycles the board maintains the programmed 45 second blower delay and steady 120 V control logic for ignitors and gas valves. Single-stage operation means output levels do not ramp; the board delivers consistent sequencing for as long as the thermostat calls for heat.

Highlights

  • Integrated control manages air cleaners, blowers, gas valves, humidifiers, ignitors and inducers
  • OEM replacement matches Lennox part numbers 100925-01, 100925-02, 100925-03 and White-Rodgers 50A66-122, 50A66-123
  • 120 V control voltage with 25 V AC input powers single-stage furnace systems
  • 45-second heat blower on-delay protects heat exchanger during startup
  • White-Rodgers 50A66-743 model ensures direct-fit compatibility for Lennox equipment

Specifications

BrandWHITE-RODGERS

Questions about this item

How do I wire the 120 V control voltage and 25 V AC input when installing this White-Rodgers 50A66-743 board?

Connect line voltage to the 120 V terminals and the transformer secondary to the 25 V AC input; the step often missed is verifying the 45-second heat blower on-delay jumper matches the furnace spec before powering up.

Which components on this Lennox-compatible board typically need replacement after several heating seasons?

The hot-surface ignitor and flame sensor are the wear items; the board itself has no user-serviceable fuses or relays listed, so plan on ignitor replacement when cracks appear.

What is the first limitation that appears when the inducer and blower run continuously on this single-stage control?

The 120 V control circuit and 25 V AC input rating set the thermal ceiling; sustained operation without adequate cabinet airflow will trip the board’s internal protection first.

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