Fenwal 35-655605-015 Control

The Fenwal 35-655605-015 is a 24VAC field-proven Hot Surface Ignition (HSI) control engineered for direct burner monitoring and gas valve modulation in commercial HVAC and process heating equipment. This microprocessor-based gas ignition control features a 10-second Trial for Ignition (TFI) period with a 0-second prepurge, specifically designed for applications requiring immediate heat response. As a three-trial ignition module, the 35-655605-015 utilizes sophisticated software logic to manage flame sensing via the ionization principle, ensuring safe burner operation. This specific Fenwal ignition board provides a 120/240VAC inducer blower output and a standard 24V gas valve control circuit. The 35-655605-015 is a drop-in OEM replacement control for various rooftop units and unit heaters, offering robust protection against nuisance lockouts while maintaining strict safety timings for gas-fired appliance sequences. Its diagnostic LED provides real-time troubleshooting data, streamlining field service calls for technicians managing Fenwal 35-65 series replacements.

• On-Board Diagnostics: Rapidly identify system faults including internal RAM/ROM failure, airflow issues, or flame signal loss using the integrated LED.
• Multi-Trial Logic: Increases reliability by attempting ignition three times before entering a hard lockout state, reducing unnecessary service calls during cold starts.
• Universal HSI Compatibility: Designed to work seamlessly with both 120VAC and 240VAC hot surface igniters for versatile application across different furnace platforms.
• Direct Spark to HSI Migration: Provides a stable platform for upgrading older 24VAC atmospheric burner systems to contemporary ignition standards.

What is the diagnostic code for a flame sense failure on this Fenwal unit?
If the control detects a flame failure during the trial period or loses signal during the run cycle, the LED will typically pulse to indicate a flame loss or improper microamp signal. Always verify the flame sensor is clean and positioned correctly in the burner flame.

Can the 35-655605-015 replace a module with a different prepurge timing?
This specific model features a 0-second prepurge. If your existing sequence of operation requires a pre-purge for combustion chamber clearing, ensure your system's inducer timing is handled externally or use the specific Fenwal suffix corresponding to your required delay.

What is the minimum flame current required for stable operation?
For the 35-655605-015, a minimum flame sense current of 0.7 microamps DC is required for the microprocessor to maintain the gas valve circuit. For optimal performance and to avoid intermittent dropouts, 1.0 microamp or higher is recommended.

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.