Resideo AT40A1139 Transformer R-407A flow enters from both Port

flow enters from both Port II (A) and Port III (B) and exits through Port I (AB)

Common Questions: Is the Peco T51-001 compatible with heat pumps

Nuisance Lockout Prevention: Provides a stable signal to the ignition module

Technicians should measure the micro-amp (µA) signal in series with the sensor wire while the burner is lit

providing consistent performance in both damper automation and hydronic system management where reliable spring-return fail-safe operation is critical for equipment protection

Resideo AT40A1139 Transformer R-407A flow enters from both PortThe Resideo AT40A1139 Transformer is a heavy duty 40VA power supply designed for reliable 24V control circuits in residential and light commercial HVACR applications. Engineered with a 240V primary and a 26. 5V secondary output, this NEMA Type D transformer ensures consistent voltage regulation for thermostats, zone valves, and gas valves. The channel frame mounting configuration allows for versatile installation directly onto a junction box or