Honeywell ST7800A1062 Purge Timer Card 90 Seconds

The Honeywell ST7800A1062 is a plug-in purge timer card that establishes a fixed 90-second prepurge interval for 7800 Series relay modules. It operates at 120-240V, 60 Hz, on a hardwired, 3-conductor line-voltage circuit, and is intended for natural gas furnace, boiler, and HVAC burner control applications in residential and commercial systems. As a non-programmable control module, it provides consistent, fixed-duration purge timing without field adjustment. This card is an OEM replacement designed for direct plug-in installation into the timer card compartment of compatible Honeywell 7800 Series relay modules and FSG controls. Symptoms indicating a failed or missing purge card include improper burner purging, a shortened purge cycle, control module error codes, or incorrect burner sequencing. Installation is straightforward, requiring only removal of the existing card and insertion of the replacement into the module socket, making it suitable for technicians performing routine control module service on compatible Honeywell equipment.