Fenwal 35-725205-021 Control

The Fenwal 35-725205-021 is a microprocessor-based Direct Spark Ignition (DSI) control engineered for precision in 120VAC gas-fired applications. Designed for heavy-duty performance, this 120v DSI control features a potted enclosure to provide mechanical stability and protection against extreme vibration or moisture washdown, making it a reliable choice for commercial cooking equipment and industrial heaters. This ignition module is configured for a 3-try ignition trial sequence with a 4-second Trial for Ignition (TFI) period. Technical specifications confirm 0 pre-purge (0PP) and 0 inter-purge timing, ensuring immediate spark and gas valve energization upon a call for heat. Field technicians value its microprocessor logic, which delivers repeatable timing sequences and safe-start hardware checks. This 35-72 series control is compatible with natural gas, LP, and manufactured gas, supporting any 120 VAC burner application under 400K BTU. The unit utilizes flame rectification technology for flame sensing, with a minimum current threshold of 1.0 µA and a rapid flame failure response time of 0.8 seconds.

• Extreme Environment Protection: The potted design ensures the 35-725205-021 maintains circuit integrity in high-vibration and washdown-prone environments.
• Optimized Ignition Sequence: Features a 3-try ignition trial with 0 pre-purge for immediate startup in critical heating cycles.
• Flexible Fuel Capability: Fully compatible with natural gas, propane (LP), and manufactured gas systems.
• Advanced Troubleshooting: Microprocessor-based diagnostic LED output simplifies the identification of ignition lockout or flame sense issues.
• Compact Surface Mounting: Small footprint designed for quick installation using standard #8 screws in tight furnace or boiler cabinets.

• What happens if the Fenwal 35-725205-021 fails to sense flame? If a flame is not sensed within the 4-second TFI, the control will attempt two additional trials. If no flame is detected after the third trial, the module enters a hard lockout and must be reset by cycling the 120V power or the thermostat call.
• How do I measure the flame current on this DSI module? Technicians should insert a DC microammeter in series with the flame sense lead. A stable reading of at least 1.0 µA is required for continuous gas valve operation.
• Can I use this control in a washdown area? Yes, the potted configuration is specifically designed to protect internal components from moisture, making it suitable for commercial kitchen and industrial applications.

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.