What should be done if a filter drier is found to be very hot during operation?

When a filter drier is found to be very hot during operation, checking the refrigerant charge and system flow is the most appropriate action to take. A hot filter drier can indicate that there might be flow restrictions or issues with the refrigerant charge.

If the refrigerant is undercharged, it can lead to improper lubrication and excessive heat generation within the system components, including the filter drier. Conversely, an overcharged system can also cause excessive pressure and heat. By verifying the refrigerant charge, you ensure that it is at the correct level to promote efficient thermodynamic performance.

Additionally, checking the system flow is critical because obstructions or restrictions in the refrigerant flow can lead to increased heat in the filter drier. If flow is inadequate, the refrigerant cannot adequately absorb heat, leading to overheating conditions. Therefore, assessing both the refrigerant charge and the system's refrigerant flow is essential to diagnose the temperature issue and ensure the efficient and safe operation of the system.

Choosing to cool the system down, replace the filter drier immediately, or increase the system pressure may not address the root cause of the overheating issue and could potentially lead to further complications or damage in the system.