York S1-331-01975-102 Control Board

The York S1-331-01975-102 is a high-performance demand defrost control board kit engineered to restore and optimize heat pump efficiency in residential and light commercial systems. This genuine York OEM replacement manages the refrigeration cycle by monitoring ambient and liquid line temperatures, initiating a defrost sequence only when ice accumulation is detected on the outdoor coil. By eliminating unnecessary timed cycles, this board reduces compressor wear and prevents liquid slugging, ensuring consistent heating performance during extreme winter conditions. This kit is a direct S1-3310197512 replacement and is compatible with York, Luxaire, and Coleman heat pumps, including Affinity and Echelon series units. The integrated microprocessor provides precise logic control, and the onboard diagnostics with LED fault codes allow for rapid troubleshooting in the field.

Key Benefits for HVAC Professionals:

• Precision Demand Defrost: Utilizes advanced sensor logic to trigger cycles based on actual frost accumulation rather than simple timers, maximizing HVAC energy efficiency.
• Direct OEM Compatibility: Ensures seamless integration with York S1-331-01975-102 specifications, maintaining the original equipment’s engineered performance levels.
• Enhanced System Protection: Integrated five-minute anti-short cycle delay and low-voltage detection protect the compressor from electrical chattering and rapid cycling.
• Configurable Defrost Curves: Features selectable jumper settings (e.g., Position 1 for reciprocating, Position 2 for scroll compressors) to tailor the defrost algorithm to the specific heat pump model.
• Field Diagnostics: Onboard LED indicators provide real-time status and fault code feedback, significantly reducing diagnostic time on service calls.

Common Questions & Technical Support:

How do I set the defrost curve on the S1-331-01975-102?
The board features a curve selection jumper. For most scroll compressors, position #2 is recommended, which includes a 30-second compressor delay when entering and exiting defrost. Position #1 is typically used for reciprocating units. Always cycle 24V power after changing jumper positions for the new settings to take effect.

Does this board replace the S1-3310197512?
Yes, the York S1-331-01975-102 control board is the designated replacement kit for several legacy defrost modules used in Johnson Controls manufactured equipment, providing updated microprocessor control and improved reliability.

What does it mean if the board shows a low-voltage fault?
This board monitors the 24VAC transformer secondary. If the voltage drops below approximately 19VAC, the board will prevent the contactor from engaging to avoid damage. A drop below 16VAC will de-energize all relays immediately to protect the control system.

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.