Indoor Control Circuit Board for Alegria Platinum TPA-36DU

ComfortStar C42790071 Indoor Control Board – OEM Logic Module for TPA-36DU Air Handlers

The ComfortStar C42790071 Indoor Control Circuit Board is a factory-specified replacement for the TPA-36DU indoor air handler units in the Alegria Platinum series. This board manages all core operational functions, including fan motor control, mode selection, safety input monitoring, and communication with the outdoor unit via inverter protocols.

Engineered for precise system regulation, the C42790071 interfaces with sensors, relays, and communication buses to ensure proper modulation and fault detection. It is designed to be mounted within the air handler's control compartment and is pre-configured for use with ComfortStar inverter systems.

Key Functional Features

• Signal Processing: Manages data from temperature sensors, float switches, and room control modules to regulate system behavior.
• Compressor Coordination: Exchanges operating data with the outdoor board to support inverter-driven modulation.
• Integrated Fan Control: Provides variable-speed fan output for improved airflow and indoor comfort.
• Diagnostic Capability: Equipped with onboard LED indicators for error code display and system status monitoring.
• OEM Harness Connections: Direct plug-in installation using original equipment connectors and layout.

Technical Specifications

• Model: C42790071
• System Type: Indoor inverter control board for TPA-36DU
• Control Voltage: 24V AC
• Application: ComfortStar Alegria Platinum inverter air handlers
• Mounting Location: Internal control panel of the indoor unit

Installation Guidance

This board should be installed by a licensed HVAC professional familiar with inverter technology. Before handling, power must be completely disconnected, and all components discharged. Verify model and serial compatibility prior to installation. Use of anti-static precautions and wiring verification tools is recommended.

• Tools Required: Multimeter, Phillips driver, and system wiring diagram
• Startup Verification: Test fan response, sensor recognition, and system communication with outdoor inverter module

Contractor Considerations

• Use OEM service documentation when diagnosing board failure or confirming replacement compatibility.
• Inspect for previous short circuits or corrosion at connectors prior to installation.
• Record diagnostic codes and clear system memory after board replacement and reboot.

Service Application

The C42790071 board is used to restore functional control to ComfortStar TPA-36DU inverter indoor units. Common replacement scenarios include failed communication, unresponsive indoor fans, or fault code indication for internal logic errors. Always use authorized replacement parts to maintain warranty and performance standards.