Fenwal 35-665575-111 Control

The Fenwal 35-665575-111 is a microprocessor-based Hot Surface Ignition (HSI) Control Module designed for reliable burner sequencing and flame monitoring in 120V heating applications. This direct ignition control features a 20-second heat-up timing for the ignitor, ensuring consistent light-off even in demanding atmospheric conditions. Engineered for professional-grade HVACR systems, it manages the combustion process with high-precision timing, including integrated pre-purge and inter-purge cycles to clear out residual gases before each ignition trial.

Built for compatibility with both natural gas and LP systems, this 120V HSI control utilizes advanced flame rectification technology to monitor the burner. The ruggedized housing is designed to withstand the thermal stress of mechanical rooms, maintaining a minimum flame sense threshold of 0.7 microamps for stable operation. This Fenwal ignition module represents the standard for furnace and boiler control, offering a diagnostic LED for rapid field troubleshooting of lockout conditions or airflow faults.

Key Benefits

• Precision Microprocessor Control: Eliminates the drift associated with analog components for repeatable 20-second ignitor warm-up cycles.
• System Diagnostics: Integrated LED status indicator provides instant feedback on fault codes, reducing downtime during service calls.
• Enhanced Safety Logic: Features automatic lockout recovery and multi-trial ignition attempts to ensure safe system operation and fuel management.
• Universal Mounting: The compact footprint allows for flexible orientation, making it a drop-in replacement for various 120VAC ignition boards.

Common Questions

What is the trial for ignition (TFI) period for this control?
This specific 35-66 series module typically utilizes a 4-to-7 second trial for ignition following the 20-second heat-up period to ensure the gas valve is only energized when the ignitor is at peak temperature.

How do I troubleshoot a 3-flash LED error code?
A 3-flash code on the Fenwal 35-665575-111 indicates an ignition lockout. You should verify the gas supply, check the ignitor for continuity, and ensure the flame sensor is clean and properly grounded.

Can this module replace 24V ignition controls?
No, this is a dedicated 120V HSI control. Always verify line voltage at the control board terminals before installation to prevent damaging the microprocessor.

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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.