Resideo - Honeywell Home AT20A1123 Standard Universal Stripped-Down Transformer

The AT20A1123 Transformer from Resideo-Honeywell Home is a Standard Universal Stripped-Down Transformer. Designed for residential combustion control systems, it converts 120V AC input to 24V AC output, delivering 19 VA of power for reliable control circuits while supporting 50/60 Hz operation. Its compact enclosure measures 2-1/4" W x 1-7/8" D x 2" H and is suitable for panel or foot mounting in tight spaces.

UL and CSA approvals confirm safety and code compliance, while the NEMA Type D enclosure protects internal components. The operating temperature range is -20 to 105 °F, making this transformer a dependable choice for residential combustion control systems that require a compact, built-for-purpose power source. Includes thermostat, gas valve, and relay for a streamlined installation.

• Model: AT20A1123 Standard Universal Stripped-Down Transformer
• Primary Voltage: 120 VAC
• Secondary Voltage: 24 VAC
• Power Rating: 19 VA
• Frequency: 50/60 Hz
• Enclosure: NEMA Type D
• Mounting: Panel or foot
• Application: Residential combustion control systems
• Approvals: UL, CSA
• Operating Temp: -20 to 105 °F
• Includes: Thermostat, gas valve, relay