Fenwal 35-665036-111 Control

The Fenwal 35-665036-111 is a microprocessor-based Hot Surface Ignition (HSI) Control engineered for precise sequencing in gas-fired HVAC systems. Designed as a robust 24 VAC solution, this module integrates an on-board inducer blower relay to manage combustion airflow before and after the burner cycle. It features a critical 15-second pre-purge (15sPP) to clear the combustion chamber and a 4-second Trial-For-Ignition (TFI) window, ensuring dependable flame establishment in residential and commercial furnaces or boilers. With three ignition attempts (3try) before entering a safety lockout, the control minimizes nuisance service calls in cold climates. The solid-state design utilizes Fenwal’s Detect-A-Flame technology for continuous flame monitoring, maintaining high system reliability. This model is a direct replacement for various OEM ignition control boards, providing a diagnostic LED for rapid troubleshooting of pressure switch or flame sense faults. The 35-66 series is ideal for technicians requiring a fail-safe gas valve control and consistent timing under varying field conditions.

• Integrated Inducer Relay: Simplifies wiring by controlling the combustion blower directly, including a 60-second post-purge for heat exchanger cooling.
• Multi-Try Ignition: The three-trial sequence increases the success rate of burner start-ups in systems with marginal gas pressure or air-pocket issues.
• Advanced Diagnostics: On-board LED provides real-time status codes, allowing for heating system troubleshooting without extra meters.
• Standardized Timing: Fixed 15-second pre-purge and 4-second TFI provide consistent, repeatable performance across diverse gas-fired appliances.
• Broad Compatibility: Supports natural, LP, and manufactured gases, functioning within a temperature range of -40°F to 176°F.

How do I reset the control after a lockout?
If the Fenwal 35-665036-111 fails to sense flame after three trials, it enters a non-volatile lockout. To reset, cycle the 24 VAC power by adjusting the thermostat or removing the power lead for at least five seconds.

What is the minimum flame current required for operation?
For stable operation and to avoid flame-dropout cycles, the flame sensing circuit requires a minimum of 0.7 microamps. Technicians should use the dedicated test pins to verify the microamp signal during the run cycle.

Can this module replace a 120V ignitor control?
This specific model is a 24 VAC control. While technical specifications for some Fenwal 35-66 series allow for field-selectable line voltage, always verify the wiring diagram and ignitor voltage (24V vs 120V) before installation to prevent component damage.

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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.