White-Rodgers 57T01-843 Relay

The White-Rodgers 57T01-843 Relay is a professional-grade 24V post purge fan delay designed for precision blower control in HVAC systems. Engineered specifically as a direct replacement for Trane part numbers C800924P01, RLY 2807, and RLY 2257, this component is essential for managing blower shut-off delay in compressor-run air conditioning and heat pump units. By utilizing an 80-second fixed off-delay, the 57T01-843 maximizes system efficiency by circulating residual cooled or heated air into the space after the compressor cycles off. Built for high-cycling reliability, the relay features normally open contacts rated at 7 FLA and 36 LRA at 240 VAC. Its compact, panel-mount design with standard quick-connect terminals ensures a straightforward installation for technicians servicing residential and light commercial air handlers. This HVAC blower time delay relay simplifies troubleshooting and restores proper post-purge functionality with exact OEM-spec timing and terminal configurations.

• Optimized Efficiency: The 80-second post-purge cycles remaining thermal energy from the coils into the ductwork, reducing overall energy consumption.
• Direct OEM Compatibility: Serves as a drop-in HVAC part replacement for widely used Trane and Emerson furnace controls without requiring bracket modifications.
• Technical Reliability: Features a 2-second on-delay to prevent nuisance trips and a robust construction rated for 1/2 HP and 3/4 HP motor applications.
• Versatile Mounting: Integral metal mounting plate facilitates secure attachment to any flat surface within the equipment control box.

• What does this relay specifically replace? It is the primary successor for Trane C800924P01, RLY02257, RLY02807, and D155079P01.
• How do the terminals line up with older models? The terminal designations (1, 3, 4, 6, T, A, B) correspond directly to the lettered and numbered terminals on original RLY02807 and RLY02257 boards.
• Can this be used for heat pump applications? Yes, depending on your electrical hookup, it can provide blower shut-off delays in both cooling and heating modes.

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.