Carrier HH84AA020 Control Board

Thermostatic expansion valves are an integral part of your refrigeration unit. They are responsible for ensuring the right dosage of refrigerant is entering the cooling coil to ensure maximum efficiency in the air conditioning of the system.    These special expansion valves come with a temperature sensor that is mounted at the end of the evaporator coil. They incorporate signals from this sensor to maintain the required temperature of the HVAC system. The thermostatic expansion valve works like a precision device that can regulate the measurements of the liquid refrigerant that flows into the evaporator of your system. This regulation in the flow of the refrigerant is essential to prevent the reverse flow of the refrigerant into the compressor of your system.    Through this mechanism, the thermostatic expansion valve successfully separates the high and low pressure sides of the refrigeration/air conditioning system. The liquid refrigerant enters the expansion ...

Keep the control board clean and dry, ensure secure electrical connections, and inspect for corrosion or loose terminals. Regular maintenance helps prevent system failures and improves reliability. Always disconnect power before servicing to ensure safety.

• No power or intermittent startup.
• Relay failure or stuck contacts.
• Communication errors with HVAC system.
• Burnt components or visible damage.
• Faulty sensor readings or control glitches.