York S1-3120A3571 Sequencer

The York S1-3120A3571 Sequencer is a critical multi-stage control component designed for 20-23 KW electric furnaces and high-output residential HVAC systems. As a genuine OEM York replacement part, this assembly utilizes a 24V coil to manage the staged activation of up to four heating elements, preventing dangerous current spikes and nuisance breaker trips during initial startup. This electric furnace sequencer relay features four sets of normally open contacts (M1-M2, M3-M4, M5-M6, M7-M8) with precise timing intervals ranging from 1 to 160 seconds for both "on" and "off" cycles. By staggering the HVAC heating element load, it ensures consistent discharge air temperatures and protects the transformer from excessive inrush current. For technicians servicing Coleman, Luxaire, or York EB20 series units, this four-stage heat sequencer provides the exact terminal orientation required for a clean, drop-in replacement, maintaining the integrity of the original system timing and sequence of operation.

• Staged Element Activation: Effectively sequences up to four heater banks to eliminate massive instantaneous electrical draws.
• Precise Timing Control: Factory-calibrated 1-160 second delay intervals ensure smooth transitions between heating stages.
• Enhanced System Protection: Minimizes thermal stress on heat strips and prevents premature wear on fan relays and contactors.
• OEM Compatibility: Exact replacement for many York, Coleman, and Luxaire models, including cross-references for 3120A357 and 3120A3571.

How do I verify the 24V coil is functioning?
Using a multimeter set to Volts AC, check for 24V across the bottom heater terminals during a call for heat. If voltage is present but contacts fail to close within 160 seconds, the internal heater has failed.

What causes a sequencer to stay "stuck" closed?
Internal contact welding or a failed bimetal disc are common issues often caused by over-amperage or high-resistance connections at the terminals. Always check your wire terminations for signs of heat discoloration.

Can this replace a two-pole or three-pole sequencer?
While this four-pole model can handle fewer stages by leaving contacts unused, always verify the timing specifications and load ratings of the original part to ensure the blower and elements engage in the correct order.

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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.