OEM Carrier Fan Timer Control Board 20054502 for Model PG8HAA036050AAJA

This is the factory OEM Fan Timer Control Board (part #20054502) for the Carrier PG8HAA036050AAJA gas furnace. Manufactured by Honeywell for Carrier, this board — also cross-referenced as the Honeywell ST9120C2010 — is the brain of the furnace's fan and ignition sequencing circuit. It controls blower on/off timing, hot surface ignition sequencing, inducer operation, and safety lockout logic. When this board fails, symptoms typically include the furnace powering on but failing to fire, the blower running continuously or not at all, fault codes flashing on the LED indicator, or the system going into hard lockout after ignition attempts.

• OEM Part Number: 20054502 | Replaces: 20054501, ST9120C2010 | Manufacturer: Honeywell for Carrier | Voltage: 24V AC control circuit | Board Type: Fan Timer / Integrated Furnace Control (IFC)
• OEM vs Generic: This is a genuine OEM board programmed with Carrier-specific fan timing delays and safety lockout sequences. Aftermarket boards may use generic timing tables that cause nuisance lockouts, shortened heat exchanger life, or voided unit warranties — OEM is always the recommended choice.
• Install Difficulty: 3/5 — Shut off power and gas before starting. Photograph all wiring harness connections before disconnecting. Transfer all connector plugs one-to-one to the new board. Tools needed: flat-head and Phillips screwdrivers, needle-nose pliers, phone camera. Allow 5 minutes after power-off before handling board to allow capacitors to discharge.
• Warranty: 1-year OEM factory warranty against manufacturing defects. Ships same business day from our warehouse when ordered before 3 PM local time.

Compatibility: Engineered as the direct OEM replacement for Carrier model PG8HAA036050AAJA gas furnaces. Also fits a wide range of Carrier, Bryant, and Payne furnace models using the ST9120C2010 board platform — verify your existing board part number against 20054502 or ST9120C2010 before ordering. Not sure? Our HVAC parts specialists confirm fitment before you buy — reach out via chat or phone. Order now and get same-day shipping on all in-stock units.