Factory Authorized Parts™ LH33WP003 Ignition Control Module | Hot Surface Ignition (HSI) | Single-Stage OEM Logic Module

The Factory Authorized Parts™ LH33WP003 serves as the primary "brain" for the combustion sequence of your furnace, functioning as the dedicated controller for safe and reliable ignition. This OEM-focused ignition control module is the specific hardware responsible for managing the 120V power sent to the Hot Surface Ignitor (HSI) and monitoring the flame rectification signal. Specifically engineered for Carrier, Bryant, and Payne gas furnace series, this module ensures the "body" of the burner assembly—the gas valve and ignitor—operates in precise synchronization. By replacing a failed or "non-sparking" module with the LH33WP003, you restore the system's ability to verify a safe burn, preventing gas buildup and ensuring your heating system exits lockout mode to provide consistent home comfort. 

Key Features

• Genuine OEM Ignition Logic: Specifically programmed to replace part number LH33WP003, maintaining factory-standard warm-up times for carbide and nitride ignitors.
• Advanced Flame Rectification: High-sensitivity circuitry fixes issues with "short-cycling" where the furnace ignites but shuts down after several seconds due to a weak flame signal.
• Integrated Safety Lockout: Automatically terminates the gas valve signal if a flame is not detected within the trial-for-ignition period, protecting your property from unburned gas.
• Microprocessor Diagnostics: Features an onboard LED or diagnostic path that helps identify if system failures are caused by the pressure switch, limit circuit, or the module itself.
• Plug-and-Play Wiring: Designed with exact-match multi-pin molex connectors to ensure a secure, vibration-resistant electrical connection to the factory harness. 

Product Details

• Brand: Factory Authorized Parts™ (Carrier/Bryant/Payne)
• Manufacturer: Carrier Global Corporation
• Part #: LH33WP003
• Weight: 0.55 lbs
• Voltage: 24 VAC (Control) / 120 VAC (Ignitor Output)
• Ignition Type: Hot Surface Ignition (HSI)
• Trial for Ignition: OEM Standard (Multi-try)
• Flame Sense: Remote or Local Rectification 

🛠️ HVAC Depot Pro Tip

Take a Picture First: Before disconnecting the 120V ignitor leads or the low-voltage control plug, photograph the module's orientation. The LH33WP003 is often mounted in tight spaces near the burner tray where wire tension can be an issue. Conduct a diagnostic check by inspecting the porcelain on your Hot Surface Ignitor; if the ignitor is cracked or has a "white spot," it can short out the new module instantly. Always verify your furnace ground is clean and free of rust, as the LH33WP003 requires a solid ground reference to accurately "see" the flame signal through the flame sensor rod. 

Cross-Reference

• Superseded / Legacy: LH33WP001, LH33WP002, P374-2000
• Drawing / OEM Equivalents: 1012-920, 1012-83-9201A, 506A-100
• White-Rodgers/Emerson Equivalents: 50A55-843 (Single-stage equivalent)
• Brand Equivalents: Carrier, Bryant, Payne, Day & Night, Totaline 

Model Compatibility

• Carrier 58 Series (Suffixes: 58STA, 58STX, 58WAV, 58PAV, 58MXA, 58MXB)
• Bryant 300 Series (Suffixes: 310AAV, 310JAV, 311AAV, 311JAV, 340MAV, 350MAV)
• Payne PG8/PG9 Series (Suffixes: PG8MAA, PG8JAA, PG9MAA, PG9MAB)
• Horizontal Units (Suffixes: 395CAV, 373LAV, 376CAV, 383KAV)