Indoor Control Circuit Board for Alegria Platinum CPA-36

ComfortStar C70790034 Indoor Control Board – OEM Controller for Inverter Air Handler Units

The ComfortStar C70790034 Indoor Control Circuit Board is a factory-authorized replacement module for select ComfortStar Alegria series inverter-driven indoor units. This control board manages critical functions including fan motor operation, system mode switching, communication with the outdoor board, and real-time monitoring of sensor inputs and safety circuits.

As a core component of the HVAC control system, the C70790034 board ensures correct sequencing of heating and cooling operations while providing diagnostics and protection logic. It is engineered for use with inverter-based indoor fan coil units and is installed within the electrical enclosure of the air handler.

Key Functional Features

• System Control Interface – Coordinates indoor fan speed, system mode (cooling/heating), and defrost signal handling via communication bus.
• Sensor and Relay Inputs – Supports temperature probes, float switches, thermistors, and fan motor feedback for system regulation.
• Communication Capable – Interfaces with outdoor inverter board and remote controller through proprietary protocol.
• Fault Indication – Includes onboard diagnostic LEDs for quick error identification and system status monitoring.
• Factory Wiring Compatibility – Designed for drop-in installation using original harness connections.

Technical Specifications

• Model Number: C70790034
• Control Voltage: 24V AC
• Application: Indoor control board for inverter fan coils
• Installation Location: Electrical compartment of indoor air handler unit
• Mounting: Fixed-position with pre-drilled fastener points

Installation Guidance

Installation of the C70790034 board requires technical knowledge of HVAC system wiring and inverter control logic. Only licensed HVAC professionals should install or service this component. Prior to replacement, verify system compatibility using model and serial number. Ensure power is fully disconnected, and anti-static precautions are taken during handling.

• Tools Required: Multimeter, insulated screwdrivers, wiring diagram for reference
• Post-Install Checklist: Confirm fan motor startup, thermostat interface, and proper signal exchange with the outdoor unit
• Warnings: Miswiring or improper grounding can result in immediate board failure or communication loss

Contractor Notes

• Use OEM part number verification to match replacement boards with system model
• Inspect connector terminals for corrosion or overheating during board changeout
• Update job records with replaced part and diagnostic findings

Use Case

The C70790034 board is used in servicing inverter indoor air handlers that exhibit control failures, fan speed inconsistencies, or signal errors to the outdoor compressor. It is essential for restoring full functionality in variable-speed systems and should be replaced with OEM components to preserve system performance and warranty integrity.