Using Compressed Air To Find AC Leak: Is It Feasible?

Identifying leakage in an HVAC system is not always easy. Other related parts in your car usually malfunction due to a lack of refrigerant.

Thus, pinpointing any leaks in the system is crucial for preventing further damage.

An HVAC technician may recommend many techniques to check for HVAC leaks, from using compressed air to find AC leak to the time-honored soap bubble test (soapy solution).

Keep reading to dive into measures of adopting compressed air, how to test for ac leak in car, and why it should be in your toolset.

Is Using Compressed Air To Find AC Leak Ok?

Using Compressed Air To Find AC Leak

Yes, absolutely. Compressed air can spot AC leaks using Nitrogen gas. An HVAC technician will drain the system of its refrigerant, replenish it with compressed nitrogen, and listen for any abnormal noises.

The hissing or whooshing sound produced by escaping nitrogen is noticeable because the nitrogen is under higher pressure than the coolant.

Although this is the preferred approach for one HVAC technician or many, it may be costly.

There are three sure signs of a leaking AC: 

Any signs of car AC leaks have potential risks. The sooner you have them tackled, the safer you are.

How To Pressure Test Car AC System?

How to find AC leak with compressed air? Ways for leak tests may vary depending on the auto AC system being evaluated. Isolate a subset of an AC system from the rest that won’t be tested.

Before testing, ensure to temporarily lock the pressure and close valves connecting the vessel or the pipe.

A nitrogen tank or on-site nitrogen generator is hooked up to an HVAC unit before testing.

The compressed air (nitrogen) will detect leaks, and it is also strong enough to push all air, debris, and other contaminants out of the HVAC unit.

Note: Feed nitrogen into the system at roughly 250 – 600 PSIG. The needed pressure range may vary, so follow the manufacturer’s guidelines.

Two stages make up a standard car AC leak test:

  • Low-pressure testing
  • High-pressure testing

Low-Pressure Testing

It is common practice to conduct this kind of test at pressures no higher than 25% of the component’s rated working pressure.

Maintaining the amount of pressure for an extended period will guarantee that the part can withstand the force without leaking.

If the first low-pressure tests pass, increase the pressure to reckon the system’s robustness under greater pressure.

High-Pressure Testing

As time goes on, the operational pressure will rise to its rated operational level. You can determine the required pressure based on the leak testing rules and the industry.

Use a soapy solution to pinpoint the exact location of leaks. It will bubble where leaks are due to the compressed nitrogen exiting.

If the aforementioned leak is seen at a given pressure, the component must be depressurized before you fix it. When you finish the repairs, you can start the pressure test again.

When the test is over, it will make the nitrogen pressure drop. Keep a small quantity of nitrogen inside to preserve the line or vessel until it is filled with its intended content (refrigerant in this case).

As such, the nitrogen shield protects the inside from air exposure.

Why Use Nitrogen For Pressure Testing?

Nitrogen gas is prevailing regarding pressure testing owing to its favorable physical and chemical qualities.

It is a non-reactive gas with the AC unit undergoing pressure testing as it is colorless, odorless, and chemically inert.

Gaseous nitrogen is used for leak test with compressed air thanks to its extra benefit of displacing moisture, oxygen, and particle pollutants inside the equipment so that it won’t expose sensitive equipment to water, corrosion, and impurities buildup.

Lastly, nitrogen during pressure testing can significantly reduce spontaneous combustion mishaps, making the testing procedure safer for everyone and any HVAC technician involved.

What Are Other Ways To Test Car AC For Leaks?

Electronic Refrigerant Leak Detector

Aside from soap solution and pressure test ac system with air, electronic leak detectors are also popular. They can sniff out certain refrigerants, so-called “sniffers,” because of this competence.

Despite being the most budget-friendly option, these handheld detectors aren’t always reliable.

Electronic leak detectors in confined spaces may be a massive hassle since they need to be placed on every leaky surface for a thorough scan.

Air Conditioner UV DYE

According to an HVAC technician, UV Dye is one of the optimal leak detection methods.

You can easily locate the leaks in the car’s AC system with Air Conditioner UV dye – a low-cost and high-quality leak detector. When exposed to ultraviolet light, A UV dye can work well.

The injectable UV dye is compatible with all refrigerant gasses, which is well-received by experts.

It does wonders in getting rid of residue and false positive pressure. Interestingly, the product facilitates finding leaks and is economical, portable, and trustworthy.

But you need to make sure you’re safe before moving on. Wear safety goggles to protect your eyes from dye splashes that could get in them.

Also, wear a face mask or respirator since a formula might irritate your nose and throat.

Our Verdicts

Why Use Nitrogen For Pressure Testing?

Using compressed air to find AC leak works wonders. The HVAC technician always brings a Nitrogen gas cylinder along while installing an air conditioner.

Nitrogen can purge oxygen out of AC to avoid the deterioration inside AC due to oxidation and subsequent damage.

Since nitrogen does not expand or contract as much when heated or cooled, it is employed for the pressure test of your car’s AC.

Drivers and car owners should make the most of compressed air or nitrogen. Not to mention, this post would help others.

Of course, this article is only my way to find the leakage. If you have another opinon on how to find it by other ways that worked with you. Let us know via our contact page here.

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