Robertshaw 780-845 Ignition Module

The Robertshaw 780-845 Ignition Module is a veteran-standard intermittent pilot ignition control engineered for reliability in gas-fired heating systems. Designed as a versatile SP845 factory model, this 24V AC unit features solid-state logic and flame rectification for precise automatic sequencing. It serves as the direct replacement for 100-00831-05 and 9004426105, effectively consolidating truck stock for service contractors. The module delivers 4 to 15 sparks per second and manages a combined load of 1.5 Amps at a 0.4 power factor. For safety, the 780-845 includes a 90-second safety lockout timing and a 2-second maximum flame failure re-ignition response. If the pilot burner flame is not sensed after three ignition attempts, the control enters a one-hour lockout period with a 6-minute purge delay between tries. Built for rugged environments, it maintains high performance in up to 95% non-condensing relative humidity and temperatures reaching 175°F.

• Universal Compatibility: Serves as a direct replacement for 9004426105 and 100-00831-05, reducing the need for multiple specialized modules.
• Advanced Diagnostics: Features an onboard green diagnostic LED that remains steady during normal operation and flashes to indicate external sensing issues.
• Enhanced Safety Logic: Employs flame rectification to continuously monitor the pilot flame throughout the heating cycle, ensuring immediate shut-off if the flame fails.
• Flexible Installation: Compact design with molded-in terminal barriers and a mounting screw that provides a positive ground connection for fast field replacement.

How do I troubleshoot a flashing LED on my Robertshaw 780-845?
A flashing green LED typically indicates a problem external to the module, such as a dirty flame sensor, poor ground connection, or an issue with the pilot flame not being sensed. If the LED is completely off during a call for heat, the control may be in internal lockout.

What is the lockout sequence for this intermittent pilot module?
The module provides 90 seconds of sparking per attempt. After three failed tries, it initiates a 6-minute purge delay followed by a one-hour lockout. You can manually override this at the thermostat to reset the sequence.

Can the Robertshaw 780-845 replace an SP745 module?
Yes, the 780-845 is the functional and technical successor to the Robertshaw SP745 series, offering updated solid-state logic for improved flame sensing reliability.

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.