Carrier HH660027 Defrost Controller

The Carrier HH660027 Defrost Controller is a high-performance direct replacement for 50BB660001, designed specifically for Carrier and Bryant heat pump systems. This HVAC control board manages the critical defrost cycle by monitoring coil temperature and compressor run time to prevent excessive ice accumulation on the evaporator. Engineered for reliability in 208/230V applications, the HH660027 features field-selectable time intervals (30, 60, or 90 minutes) and integrated short cycle protection to ensure compressor longevity. Whether you are troubleshooting a defrost board failure or performing a system upgrade, this OEM-spec part provides precise control of the reversing valve and outdoor fan motor. Integrating this Carrier defrost board into your maintenance routine ensures optimal heat transfer and prevents the efficiency loss associated with frosted coils. Its robust design is built to withstand harsh outdoor environments, making it the preferred choice for professional contractors seeking a reliable Carrier heat pump replacement part.

• OEM Compatibility: Serves as the official direct replacement for 50BB660001, ensuring exact fit and pin-to-pin wiring compatibility for Carrier and Bryant units.
• Adjustable Defrost Intervals: Features selectable jumpers for 30-, 60-, and 90-minute cycles to optimize performance based on local climate conditions.
• Short Cycle Protection: Built-in 5-minute delay prevents rapid compressor cycling, reducing mechanical stress and preventing premature component failure.
• Diagnostic Support: Includes test pins for forced defrost and manual override, streamlining the defrost controller troubleshooting process during service calls.
• High-Voltage Durability: Rated for standard 208/230V 50/60 Hz operations, meeting rigorous technical standards for residential and light commercial heat pumps.

How do I test the defrost cycle on the HH660027?
Technicians can force a defrost cycle by momentarily shorting the "speed-up" or "test" pins with a screwdriver while the system is in heat mode. If the reversing valve shifts and the outdoor fan stops, the board logic is functioning correctly.

Will this board work with non-communicating systems?
Yes, the HH660027 is designed for standard 24V control circuits. When replacing older Carrier defrost control boards, ensure you reference the original wiring schematic as terminal designations (like T1 or DFT) must match the sensor inputs.

What are the signs of a failing defrost controller?
The most common indicators are a completely frozen outdoor coil, the unit staying in defrost too long, or the compressor tripping on high pressure. Always verify the defrost thermostat (DFT) and sensors before condemning the board.

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.