How to Read an Automotive Air Conditioning Refrigerant Gauge?
2 Answers
How to read an automotive air conditioning refrigerant gauge, detailed instructions are as follows: 1. Automotive air conditioning high-pressure and low-pressure ports: Connect the refrigerant charging gauge. Turn on the car's air conditioning and let it start working. 2. Observe the gauge readings: Under normal conditions, the low pressure should be maintained between 3-4, and the high pressure between 10-15. 3. Check the outermost numbers on the gauge: If the readings exceed the normal range, it indicates a problem somewhere. 4. Refrigerant should be charged appropriately: Follow the gauge readings, and do not only look at the low pressure while ignoring the high pressure. Not all cases of air conditioning not cooling are due to a lack of refrigerant. Before adding refrigerant, it is necessary to determine whether the air conditioning has refrigerant and whether it needs to be added. If refrigerant needs to be added, then proceed; if not, the lack of cooling is due to other reasons.
The A/C refrigerant gauge is something I'm most familiar with after over a decade in auto repair. The gauge typically has two needles indicating high and low pressure. The low-pressure gauge connects to the blue hose to measure suction line pressure – with the engine running and A/C on, normal readings should be around 30-50 psi. The high-pressure gauge connects to the red hose to measure compressor discharge pressure, which should fall between 150-250 psi in hot weather. Watch for excessive needle fluctuation which may indicate air contamination. If pressure drops below minimum, refrigerant recharge is needed. Ideal operation temperature is 25°C ambient – simultaneously feel the A/C lines for temperature differentials. Only take readings when the needle stabilizes for accuracy.
