Where are low pressure limit controls usually installed?

Low pressure limit controls are typically installed on the suction line of a heat pump to monitor and protect the system from low refrigerant pressure conditions. These controls help prevent potential damage to the compressor by shutting down the system when the suction pressure falls below a predetermined level, indicating that there may be an issue such as low refrigerant charge or a restriction in the system.

By placing the control on the suction line, it directly measures the pressure that the compressor is experiencing. If the pressure drops too low, it suggests that the heat pump may not be able to operate effectively or safely. Ensuring that the compressor does not run under inadequate pressure conditions is crucial for maintaining system reliability and efficiency.

The installation of low pressure limits on other components, such as the condenser coil or discharge line, would not provide the same level of protective monitoring and could risk compressor failure. Additionally, placing them within the indoor air handling unit would not accurately reflect the refrigerant pressures critical to compressor operation.