Fenwal 35-755900-009 Circuit Board

The Fenwal 35-755900-009 is a microprocessor-based Hot Surface Ignition (HSI) Control Board engineered for precise sequence timing and reliable flame supervision in 120 VAC gas-fired appliances. This MARK17DU-117 series module utilizes DETECT-A-FLAME technology to ensure robust flame sensing sensing across natural, LP, and manufactured gas applications. Designed for versatile field integration, it supports both local and remote flame sensing and can drive hot surface igniters up to 5 Amps. The 35-755900-009 circuit design offers customizable pre-purge and inter-purge timings, providing technicians with a flexible solution for tube heaters, commercial cookers, and construction heaters. With a compact open board with standoffs configuration, it facilitates rapid installation in space-constrained cabinets. The system is built for industrial-grade durability, featuring diagnostic LED indicators and dedicated flame current test pins to streamline troubleshooting and verify microamp signal strength during routine maintenance.

• Enhanced Safety: Integrated DETECT-A-FLAME technology provides instantaneous response to flame failure, preventing hazardous gas accumulation.
• Precision Timing: High-performance microprocessor control ensures repeatable ignition sequences and accurate trial-for-ignition periods.
• Broad Compatibility: Optimizes performance for various 120V HVAC ignition systems, supporting both single and multi-try ignition profiles.
• Field Diagnostics: Built-in flame current test points allow contractors to measure DC microamps without breaking the circuit.
• Reliable Construction: Designed to withstand ambient temperatures up to 175°F, ensuring stable operation in high-heat environments.

How do I reset the Fenwal 35-755900-009 after an ignition lockout?
Lockout recovery is achieved by cycling the thermostat call for heat or removing the 120 VAC power source for a minimum of 5 seconds to clear the internal microprocessor logic.

Can this board be used with both local and remote flame sensing?
Yes, the 35-755900-009 is engineered for maximum flexibility, allowing for either local sensing through the igniter or remote sensing via a dedicated flame rod.

What should the flame signal reading be for this module?
Technicians should verify a minimum flame current of 1.0 microamp DC at the FC+ and FC- test pins using a high-quality digital multimeter to ensure reliable operation.

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.