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Diagnosing AC Pressures Using Auto Refrigerant Gauges

Diagnosing AC Pressures Using Auto Refrigerant Gauges

Refrigerant is a gas that changes states and temperature by increasing or decreasing pressure. The refrigerant will probably not get cold enough, or at all if the pressure in any system component is not at the necessary PSI. You can better diagnose AC pressures and common problems by using auto refrigerant gauges.

Every automobile has an onboard air conditioner as standard equipment. Still, some people will notice that their car's air conditioner isn't as cool as it was when they originally got it. There's likely a problem with the air-conditioning pipeline's pressure in this scenario. We can utilize the automotive air-conditioning pressure gauge at this point to see if the automobile air-conditioning refrigeration system is broken.

Reading AC Pressures Using Auto Refrigerant Gauges

Multiple reading units, such as MPA, bar, KPA, and psi, are included on the air-conditioning pressure gauge. Everyone should be aware of the unit of measurement (1mpa=10bar=1000kpa=145psi).

The atmosphere, engine speed, condenser cooling conditions, and other elements all influence the pressure value of automotive air conditioners. High-pressure gauges and low-pressure gauges are the two automotive air-conditioning pressure gauges. The red gauge indicates high pressure, whereas the blue gauge indicates low pressure.

There's no such thing as a constant standard. For example, if the outside temperature is 20 degrees Celsius, the high-pressure value of the automotive air conditioner is 1.3-2.0 mpa, while the low-pressure value is 0.12-0.25 MPA. The high-pressure value of 1300-1600kpa and the low-pressure value of 150-250kpa while operating the automotive air conditioner are normal if the engine speed is maintained at 1500-2000r/min, for example.

Common Diagnosis of Car Ac Problems

To begin, measure the pressures at idle and note the HIGH and LOW side pressure measurements. These pressures will vary based on ambient temperature (the temperature of the surrounding atmosphere), but you should aim for a low side pressure of 30-40 psi and a high side pressure of 150-175 psi. If one or both of these parameters are not met, use the options below to investigate your issue further.

Not Enough Refrigerant or Failing Compressor

Both the low-pressure and high-pressure gauges are lower than the average. It's is a fairly regular occurrence. We can directly inject refrigerant to remedy the problem in some cars with long service life and a slow refrigerant leakage failure.

Rev the engine to 2000 RPM with the instruments connected and observe the pressures in the AC system. Do they get closer (the high side gets lower, while the down side gets higher), or do they get further apart? Start by emptying and recharging the system, then retesting if they move away from each other.

Before reassembling an AC system, replacing AT LEAST the compressor, expansion valve, receiver/drier, and flushing the evaporator, condenser, and lines are necessary. The condenser and manifold lines on some vehicles, such as many Fords and Chevys, will need replacement. They are difficult to flush dirt from due to their design. If they move together, you have a faulty compressor, and you should replace the system. If any debris remains in the system after a compressor replacement, you could be setting yourself up for future compressor failure if the debris loops back to the original compressor.

The drier goes into the condenser in certain systems, such as many Hondas. After replacing the parts, you should evacuate and recharge the system. You've just spent a big amount of money on a new system, as well as time and money to install it. Make certain that the project is completed correctly. "Wait till you hire a beginner if you think hiring a professional is pricey."

Failing Expansion Valve

Both the low-pressure and high-pressure gauges have higher readings than the average. The cooling effect of the car is poor since the expansion valve has been left open for a longer length of time. It results in a mixture of high and low pressures. To fix the problem, replace the expansion valve.

Low-pressure gauge readings reveal vacuum, whereas high-pressure gauge readings are lower than average. It will not cool the automobile if the air conditioner fails to the point where a low-pressure gauge connects straight to the vacuum. The evaporator expansion valve is held closed in this sort of failure, and you must replace the expansion valve.

Abnormal Low Pressure/High-Pressure Gauge Reading

If you find yourself in this circumstance, it means there is water in the system. When the water in the pipeline freezes, it creates a vacuum in the low-pressure pipeline. The system returns to normal once the ice has melted. Release the refrigerant from the system, re-evacuate, and replace the refrigerant at this time.

Failing Air Conditioner Compressor

The low-pressure gauge reads higher than the usual reading, whereas the high-pressure gauge reads lower.

If this situation occurred in the pressure gauge, there's a lot of refrigerant in the pipeline. Then, the air conditioning effect is poor, the failure of the air conditioning compressor must be considered. You can solve this problem by replacing the compressor.

Under Charged or Too Much Oil in the System

Visually inspect the system for any leaks. It might spill out somewhere if you're low on refrigerant. Examine the hose ferrules and fitting connectors at the condenser, compressor, evaporator, or expansion device for oil residue. If there's no evident leak, collect the refrigerant, repair the service ports or valves. Then, empty and recharge the system, and add dye if you discover another leak.

Diagnosing AC Pressures Using Auto Refrigerant Gauges

These are just a few examples of what could go wrong. Keep in mind that each vehicle is unique, and there is a variety of controlling and monitoring devices that can cause your air conditioning to malfunction. If you need help with a specific vehicle, talk to your local mechanic or give us a call now.

HVAC specialists and individuals in Australia can purchase auto refrigerant gauges from HVAC Shop. We also have other HVAC products that may be useful for your air conditioning company!