ASE G1 Auto Maintenance and Light RepairHeating and Air Conditioning (HVAC)Easy
Which of the following is the standard method for determining the correct refrigerant charge amount for an automotive AC system after a repair?
- AAdding refrigerant until the vent temperature is consistently cold.
- BAdding refrigerant until the low-side pressure reaches 40 psi.
- CUsing a sight glass to observe refrigerant flow until clear.
- DWeighing the refrigerant charge according to manufacturer specifications.
Show answer & explanationAnswer & explanation
Correct answer: D. Weighing the refrigerant charge according to manufacturer specifications.
The only accurate method for charging an automotive AC system is to weigh in the exact amount of refrigerant specified by the vehicle manufacturer, typically found on an underhood label or in service information.
Why the other options are wrong
- A. Vent temperature is a symptom of system operation, not an accurate measure of refrigerant charge.
- B. Pressure readings can vary greatly with ambient temperature and humidity, making them unreliable for precise charging.
- C. Sight glasses are not always present and can be misleading, as clear flow doesn't guarantee correct charge.
Refrigerant Charging Method
The procedure for adding the precise amount of refrigerant to an automotive AC system to ensure optimal performance and efficiency.
- Must follow manufacturer's specifications.
- Requires a digital scale for accuracy.
- Incorrect charge can damage the system or reduce performance.
Memory trick: Weight Wins When We Charge.