Fenwal 35-705501-003 Control

The Fenwal 35-705501-003 is a dedicated 120VAC Direct Spark Ignition (DSI) control designed for precise gas burner management in commercial and industrial HVACR applications. This microprocessor-based ignition module features a 7-second Trial for Ignition (TFI) period and is engineered for single-try configurations. As a non-prepurge (NoPP) unit, it initiates the spark sequence immediately upon the call for heat, making it an essential component for systems requiring rapid ignition cycles. The 35-705501-003 120V DSI utilizes remote flame sensing technology to monitor the burner flame through the spark electrode, ensuring safe operation and immediate gas valve closure upon flame failure. This Fenwal ignition board is a common replacement in gas-fired furnaces and boilers where line voltage control and flame rectification are required. Contractors often specify this intermittent pilot ignition module for its robust diagnostic LED and standard terminal spacing, which simplifies field retrofits and troubleshooting in high-demand environments.

• Instant Ignition Sequence: The zero-prepurge design allows for immediate sparking, reducing lag time in heat-heavy applications.
• Precise Timing: Features a factory-set 7-second TFI to ensure reliable light-off while maintaining safety standards.
• Single Try Logic: Engineered for one-trial ignition systems, providing a simple and predictable lockout sequence if flame is not established.
• Enhanced Diagnostics: Built-in diagnostic LED provides flash codes for rapid troubleshooting of internal failures or flame sense issues.
• Robust Voltage Handling: Designed for standard 120V AC input, compatible with a wide range of commercial burner circuits.

Is the 35-705501-003 compatible with local or remote flame sensing?
This specific model is configured for remote flame sensing, meaning it requires a separate electrode or a dedicated circuit to monitor flame rectification back to the control board.

How do I troubleshoot a lockout on this Fenwal DSI module?
Check the diagnostic LED for specific flash patterns. If the unit fails to establish a flame within the 7-second TFI, it will enter a lockout state. Ensure the 120V power supply is stable and the ground circuit is continuous to avoid nuisance tripping.

Can this control be used in outdoor rooftop units?
Yes, provided it is installed within a NEMA-rated enclosure. The microprocessor-based design is moisture-resistant, though consistent exposure to high humidity or vibrations should be mitigated during installation.

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.