Fenwal 35-652500-001 Microprocessor-Based Hot Surface Ignition Control is designed for dependable automatic ignition sequencing in compatible gas-fired HVAC, furnace, burner, and heating equipment.

This control module supports a 24 VAC control circuit with field selectable 120/240 VAC, 50/60 Hz line voltage, helping service technicians match the module to the required installation voltage. Its microprocessor-based operation manages hot surface ignition timing, valve output, flame response, lockout protection, and system diagnostics for stable burner startup and controlled heating system operation.

The integrated LED diagnostic indicator helps identify control fault, flame/no call for heat, and ignition lockout conditions, reducing troubleshooting time during service.

Key product details include 24 VAC input at 50/60 Hz, 300 mA, 24 VAC valve output rated 2.0 A max, 24 VAC ignitor output rated 5.0 A max, 0-second pre-purge, 5-second ignition timing, 5-second heat-up timing, and an operating ambient range of -40°F to +176°F.

Built for replacement and service applications where Fenwal 35-652500-001 is specified, this hot surface ignition control helps restore reliable ignition performance and consistent heating system operation.

 

Frequently Asked Questions
 

• What is the Fenwal 35-652500-001 used for?

The Fenwal 35-652500-001 is a microprocessor-based hot surface ignition control used to manage automatic ignition sequencing in compatible gas-fired HVAC, furnace, burner, and heating equipment.

• What input power does this ignition control require?

This Fenwal ignition control uses 24 VAC input power.

• Does the Fenwal 35-652500-001 support different line voltages?

Yes.  The ignitor input line voltage is field selectable for 120/240 VAC at 50/60 Hz, allowing the control to be matched to the required installation voltage.

• What is the ignition timing for this control module?

The Fenwal 35-652500-001 has a 4-second time for ignition, also referred to as 4-second TFI.

• Does this model have pre-purge or inter-purge timing?

Yes.  The listed pre-purge and inter-purge timing is 0 seconds.

• What is the heat-up time?

The heat-up time is 20 seconds.

• Does the Fenwal 35-652500-001 include automatic reset?

No.  This model is listed as 1 TFI without automatic reset.

• What gas types are compatible with this ignition control?

The Fenwal 35-652500-001 is compatible with natural gas and LP, or liquid propane gas, applications when used with properly matched equipment.

• What operating temperature range does this control support?

The operating temperature range is -40°C to +80°C, equivalent to -40°F to +176°F.

• Does this ignition control include diagnostics?

Yes.  The control includes an onboard LED diagnostic indicator designed to support faster troubleshooting during service.

• What does the LED diagnostic indicator help identify?

The LED diagnostic indicator helps identify operating or fault conditions such as control faults, ignition issues, and lockout-related conditions.

• What is the benefit of microprocessor-based ignition control?

Microprocessor-based control provides precise and repeatable timing sequences, helping support consistent ignition operation and full-time flame sensing.

• Does this control include a false flame safety check?

Yes.  The safe start check helps prevent the gas valve from opening if a false flame is detected before ignition.