Fenwal 35-655705-001 Control

The Fenwal 35-655705-001 Control is a rugged, microprocessor-based 24VAC Hot Surface Ignition (HSI) module engineered to manage specialized gas-fired combustion sequences in high-demand HVACR systems. This unit is specifically configured with 0-second prepurge (0pp) and 0-second inter-purge (0IP) timings, delivering an immediate trial for ignition upon a call for heat. As a 3-try ignition control, it provides three distinct attempts to establish a flame before entering a safety lockout, ensuring operational reliability in fluctuating conditions. With a 5-second Trial for Ignition (TFI) window, it is ideally suited for pool heaters, commercial boilers, and gas furnaces where rapid ignition is a technical requirement. The board supports field-selectable line voltage for 120/240 VAC ignitors and features DETECT-A-FLAME® flame sensing technology for precise monitoring. For the technician, the on-board diagnostic LED and dedicated flame current test pins streamline the troubleshooting of lockout recovery and flame signal strength in the field.

• Rapid Ignition Sequence: Features 0-second prepurge for immediate burner activation upon 24V signal.
• Multi-Try Reliability: Configured for 3 ignition attempts to prevent nuisance lockouts during cold starts or gas pressure fluctuations.
• Precise Flame Sensing: Utilizes 0.7 microamps minimum flame sensitivity to ensure safe and continuous burner operation.
• Contractor-Friendly Diagnostics: Integrated LED flash codes provide instant feedback on airflow faults, flame failures, and internal circuit health.
• Broad Compatibility: Suitable for natural gas, LP, or manufactured gas systems in applications up to 400K BTU.
• Flexible Ignitor Support: Accommodates 24V, 120V, or 240V mini-ignitors through field-selectable line voltage pins.

What is the lockout recovery procedure for this Fenwal module?
Lockout recovery requires a manual reset. You must either cycle the thermostat (remove the call for heat) or interrupt the 24VAC power supply to the module for at least 5 seconds.

Can I use this to replace a single-try ignition module?
While this 35-655705-001 offers 3 trials for ignition, always verify the appliance manufacturer’s specifications. This model is designed for applications where a 5-second TFI and 0-second prepurge are required for safe combustion.

How do I check the flame signal on this unit?
Use a DC microammeter connected to the flame current test pins on the board. A stable reading above 0.7 microamps is required to maintain the gas valve circuit.

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.