Fenwal 35-665535-113 Control

The Fenwal 35-665535-113 Control is a microprocessor-based hot surface ignition (HSI) module engineered to handle automated sequencing and flame monitoring in 24 VAC gas-fired heating systems. This Fenwal replacement ignition board features an integrated combustion blower relay with a 60-second post-purge and a 15-second pre-purge, optimizing airflow before and after the heating cycle. Designed for high-reliability start-ups, the igniter control sequence utilizes a 3-try ignition logic with a 7-second Trial for Ignition (TFI) window. Its dual-voltage capability allows for 120/240 VAC field-selectable line voltage, ensuring compatibility with various HSI ignitor configurations. Technicians can utilize the on-board LED diagnostics for rapid field troubleshooting, while the dedicated flame current test pins facilitate precise microampere monitoring. This non-integrated module is a robust solution for contractors needing a dependable gas furnace ignition control that supports both local and remote flame sensing across natural, LP, and manufactured gas applications.

• Precision Timing: Microprocessor logic ensures repeatable 15-second pre-purge and 7-second TFI cycles for consistent burner performance.
• Simplified Troubleshooting: On-board diagnostic LED identifies system faults, reducing diagnostic time during service calls.
• Flexible Applications: Field-selectable 120/240V line voltage supports multiple ignitor types within a single SKU.
• Enhanced Safety: Integrated pressure switch monitoring and non-volatile lockout with manual reset provide fail-safe gas valve control.
• Flame Sensing Versatility: Supports both local (through the ignitor) and remote flame sensing to fit various OEM burner designs.

What does the LED flash code indicate on the 35-665535-113?
The diagnostic LED provides real-time status; a steady "on" typically indicates normal operation, while specific flash patterns identify issues like airflow faults, flame signal loss, or internal control failure.

How do I measure the flame signal on this Fenwal module?
Use a micro-ammeter connected to the FC+ and FC- test pins. A stable reading of 1.0 µA DC or higher is required to maintain the gas valve circuit and prevent nuisance lockouts.

Can this control replace older 35-65 or 35-66 series modules?
Yes, provided the timing specifications (15s pre-purge, 7s TFI) and voltage requirements match. Always verify the wiring harness compatibility as this is a 24 VAC microprocessor-based unit.

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.