McQuay Daikin 803005073 Circuit Board

The McQuay Daikin 803005073 is a 24VDC Auxiliary Relay Circuit Board engineered for precision control within commercial and industrial HVAC systems. This OEM replacement part is specifically designed to facilitate reversing valve conversion from DC to AC solenoid coils, making it a critical component for technicians performing upgrades or repairs on McQuay Water Source Heat Pump (WSHP) units. By integrating with high-performance Mark IV control boards, this auxiliary relay ensures seamless switching of auxiliary circuits, maintaining the operational integrity of the reversing valve and entire refrigerant circuit.

Constructed for durability in demanding mechanical environments, the 803005073 relay board features a 24VDC coil with contact ratings of 3A at 300VAC/30VDC. It serves as a direct drop-in replacement for legacy part numbers 03005073 and 106059701. This board eliminates compatibility issues during field retrofits, ensuring that the HVAC control system maintains precise timing and electrical isolation required for long-term system reliability and efficient heating/cooling cycles.

• Direct OEM Compatibility: Specifically designed for Daikin McQuay systems, ensuring plug-and-play installation without field modifications.
• Enhanced Circuit Control: Provides reliable switching for auxiliary HVAC circuits, protecting primary control boards from voltage spikes.
• Versatile Conversion: Essential for WSHP reversing valve conversion, allowing legacy units to utilize modern solenoid coils.
• Industrial Build Quality: Features 3A contact ratings, optimized for the high-duty cycles of commercial ventilation and climate control applications.

Is this board compatible with both Mark IV and older control systems?
Yes, the 803005073 is designed to bridge the gap between older DC systems and newer AC solenoid requirements when used with the appropriate Mark IV PC board configuration.

Does this part replace the 03005073?
Correct. This is the official Daikin replacement for part numbers 03005073 and 106059701, maintaining identical electrical specifications and footprints.

What is the primary function of the 24VDC coil in this application?
The 24VDC coil acts as the trigger mechanism to switch the auxiliary relay contacts, enabling the control of higher voltage reversing valves or auxiliary fans from a low-voltage control signal.

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.