What two actions are used to remove non-condensables and moisture from a refrigerant system?

• A. Filter dryers and flushing the system
• B. Pumping down to vacuum only
• C. Adding more refrigerant
• D. Replacing compressor oil

Answer: (A)

Moisture and non-condensables in a refrigerant system are best dealt with by a combination of filtering and purging. A filter-dryer is placed in the refrigerant circuit to trap moisture and contaminants as the refrigerant circulates, protecting the system from acid formation, corrosion, and clogged components. Flushing the system, on the other hand, pushes a cleaning solvent or purge through all lines and components to physically remove any remaining non-condensables and debris, along with any residual oil or moisture that the dryer hasn’t captured.

Together, these steps ensure the system is clean and dry before recharging. Pumping down to vacuum alone isn’t as reliable for removing all pockets of air and moisture, adding more refrigerant doesn’t remove moisture, and replacing compressor oil addresses oil contamination but not moisture throughout the circuit.