An overcharge of refrigerant will cause which condition?

• A. Decreased head pressure
• B. No change in head pressure
• C. Overcooling the suction reduces head pressure
• D. Increased head pressure

Answer: (D)

Overcharging adds more refrigerant mass that the condenser must reject. With a fixed ambient condition, the condenser can only remove a certain amount of heat at a given temperature. When there’s extra refrigerant circulating, the condenser has to condense more vapor, so the condenser temperature and pressure rise until the system reaches a new balance. That higher condenser pressure translates to increased head (high-side) pressure. The excess charge can also push liquid back toward the compressor, raising discharge temperature and contributing further to higher head pressure.