Fenwal 35-725200-005 Control

The Fenwal 35-725200-005 is a robust 120V Direct Spark Ignition (DSI) control module engineered for high-reliability startups in gas-fired heating equipment. This micro-processor-based control is a critical OEM replacement ignition module for residential and commercial furnaces, boilers, and water heaters. Operating on a single-try ignition sequence with a 10-second Trial for Ignition (TFI), it ensures precise flame detection and lockout control. The integrated potentiometer and multi-pin configuration allow for seamless field integration into existing wiring harnesses. Designed to withstand the rigors of heavy-duty HVACR environments, this 120VAC gas ignition control provides the rapid response required for safe burner management. Whether you are servicing a rooftop unit or an indoor furnace, the Fenwal 35-72 ignition series remains the industry standard for direct spark ignition systems, offering superior flame sensing and immediate shutdown upon pilot failure or flame loss.

Key Benefits for Contractors

• Standardized 120V Operation: Designed for high-voltage direct spark applications, reducing the need for additional step-down transformers in specific burner configurations.
• Precision Timing: The fixed 10-second TFI provides a sufficient window for consistent combustion without excessive gas accumulation.
• Flexible Integration: The multi-pin connector and compact footprint (6.2" x 4.1" x 2.7") ensure compatibility with a wide range of mounting brackets and OEM harnesses.
• Advanced Flame Sensing: Utilizes sophisticated circuitry to monitor flame rectification, preventing unsafe conditions during the ignition cycle.
• Direct OEM Match: Eliminates the guesswork and field-modification risks associated with universal "one-size-fits-all" components.

Common Questions

What is the difference between this and a 24V DSI module?
The Fenwal 35-725200-005 is strictly a 120V ignition control. Using 24V on this unit will prevent operation, and attempting to use this on a 24V system will result in immediate component damage. Always verify your secondary transformer output before installation.

Does this module support multiple ignition attempts?
No, this specific model is a 1-try ignition control. If a flame is not sensed within the 10-second TFI window, the module will enter a safety lockout. To reset, power must be cycled at the thermostat or the main disconnect.

Can I use this to replace a different 35-72 series module?
Compatibility depends on the specific suffix. While the base 35-72 series shares dimensions, the 5200-005 designation specifies 120V input and 10s TFI. Check your original part number to ensure timing and voltage match perfectly to maintain system safety and certified performance.

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.