The 50A55-743 is an automatic gas interrupted ignition control that employs a microprocessor to continually monitor, analyze, and control the proper operation of the gas burner, inducer, and fan. signals interpreted during continual surveillance of the thermostat and flame sensing element initiate automatic ignition of the burner, sensing of the flame, and system shutoff during normal operation. these controls incorporate system fault analysis for quick gas flow shutoff , coupled with automatic ignition retry upon sensing a fault correction. it is designed as a replacement for the following controls.

White-Rodgers™ Replacement Integrated Furnace Control, 25 VAC, 0.45 A, 5 - 93% RH Humidity, Surface Mounting, -40 to 176 deg F, 4-3/8 in W x 5-7/8 in H x 1-1/4 in D

• Twinning connection
• Fused to protect low voltage system transformers
• 120 VAC igniter output
• 120 VAC humidifier output
• 120 VAC electronic air cleaner output
• 120 VAC two speed PSC circulator output
• 5 A fuse protection
• Furnace status LED
• Heat fan OFF delay (dipswitch selectable)
• 1.5 A valve relay
• 6 A igniter relay
• 2.2 A full load - 3.5 A locked rotor inducer relay
• 14.5 A full load - 25 A locked rotor circulator relay
• 1 uA DC minimum current
• 0.10 uA DC uAx current
• 100 Mohm leakage resistance
• Maximum timing specification
• 0.8 sec flame establishing
• Flash code diagnostics

• Catalog https://assets.unilogcorp.com/267/ITEM/DOC/White_Rodgers_50A55_743_Catalog.pdf