Nordyne 920338 Defrost Board

The Nordyne 920338 Defrost Board is a critical OEM replacement part engineered for high-performance heat pump condensing units across the Nortek family of brands, including Intertherm, Miller, and Frigidaire. This adaptive defrost control module utilizes a sophisticated algorithm to monitor outdoor coil temperature and system run time, ensuring the reversing valve and outdoor fan operate only when necessary to clear frost coverage. By replacing outdated or failed 624700 or 920338R boards, technicians can restore efficient heating cycles and prevent compressor strain caused by excessive ice accumulation.

Built for 24V AC control circuits, this board features LED status indicators for real-time HVAC diagnostics and configurable jumper pins for adjusting defrost intervals (30, 60, or 90 minutes). The integrated low-pressure switch inputs and sensor-open/short detection provide a fail-safe lockout to protect the refrigeration circuit during extreme ambient conditions. Designed for a direct "plug-and-play" fit, it includes the factory-mounted harness connector to streamline field installation for HVAC contractors.

Key Benefits

• OEM Compatibility: Exact replacement for Nordyne 920338, 920338R, and 624700 models, ensuring proper terminal alignment.
• Adaptive Defrost Logic: Minimizes unnecessary cycles, reducing wear on the reversing valve and improving overall system SEER ratings.
• Field Diagnostics: Onboard LED indicators allow for rapid troubleshooting of sensor faults or system delays without extensive probing.
• Customizable Settings: Onboard jumpers allow technicians to select optimal timing based on local climate and heat pump demand.

Common Questions

How do I test if the defrost board is initiating correctly?
Technicians can use the "Speed Up" test pins to bypass the internal timer and force a defrost cycle. If the board fails to energize the reversing valve or cut the outdoor fan during this test, the logic circuit or relay likely requires replacement.

Does this board support demand-based defrost or timed defrost only?
This module supports both hybrid timed and sensor-driven logic. It requires a valid input from the ambient sensor and coil sensor to determine if frost accumulation justifies a cycle, preventing "false defrosts" that waste energy.

What are the symptoms of a faulty 920338 board?
Common indicators include the outdoor unit becoming a "block of ice," the outdoor fan failing to stop during a defrost call, or the system getting stuck in heating mode without ever engaging the defrost heaters or reversing valve.

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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.