Common Questions About Aircon Gauges Answered

Aircon Gauges

We'll try and answer all of the common questions we receive about aircon gauges!

The pressure of the refrigerant is checked using manifold aircon gauges. Most refrigerant cans on the marketplace nowadays come with a built-in gauge. However, it will only tell you the low side pressure. On the other hand, manifold gauge sets allow you to measure low and high side pressure. They also inform you of the maximum vacuum level which can maintain during the vacuuming step.

In this article, we'll answer the most common questions about aircon gauges that even you may have in mind. Our HVAC experts will try their best to cover everything you need!


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Common Questions About Aircon Gauges Answered

What Are Aircon Gauges?

Air conditioning gauge manifolds were constructed using a chamber design. It regulates gas or pressure flows, including high pressure and compound. The AC gauges have three main chambers:

  • right side – high-pressure chamber
  • middle side – utility chamber
  • left side – low-pressure chamber

When an HVAC technician connects the manifold refrigerants gauges to the AC unit, he joins the gauge's left side (low pressure) to the AC's low-pressure side. The technician will link the high pressure of the ac unit to the right side of the gauge tube. He will read the discharge line pressure. The centre or utility chamber links to the vacuum pump's hose. It's for removing or adding refrigerants in air conditioning units.

How Does an AC Gauge Work?

Air conditioning gauges have a fairly basic mechanism: the opening and closing of the hand valve do all of the work. A needle and a small port are located in the utility chamber. Or on the other side of the low-pressure chamber from the high-pressure chamber in the AC assembly. You must crank the hand valves counterclockwise to access the utility's chamber low-pressure port if you wish to open the hand valves for low pressure. Similarly, you must rotate the utility chamber's low-pressure port clockwise to close it. The high-pressure hand valve follows the same procedure. It would help if you open the AC gauge by turning it counterclockwise. It must be closed by rotating it clockwise.

The air conditioning unit's low side or the suction line connects to the low-pressure hoses. Then, the low-pressure chamber will quickly show the pressure without the need to open anything. The steps are the same in the high-pressure chamber. You'll need to access the mid side port if you want to extract or add refrigerant, vacuum the system, or transport refrigerant into the cylinder (utility chamber). Within the utility hose, you'll discover all of the necessary accessories. You'll need to attach your HVAC gauges to your central ac unit to read the temperature and pressure within a closed system.


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Why Do I Have To Use Aircon Gauges?

There are numerous air conditioning gauges available for AC repair. Regardless, their goal is to assist experts who service HVAC equipment in maintaining a close check on the pressure within the units. They also allow personnel to determine when refrigerant needs removing or adding. It also determines the quality and kind of refrigerant detected inside the system. All of these requirements are met by an HVAC gauge. The gauge is used to describe the overall assembly, including all of the separate gauges.

An HVAC gauge's primary role is to determine the pressure and temperature in a closed system properly. The technician can tell if your air conditioner is working properly or needs repair. He will base it on these readings and measurements. An HVAC gauge will pinpoint the problem if your air conditioner is not cooling adequately or if some rooms of your house are warmer than others. It's true for air conditioning equipment installed in homes, hospitals and food warehouses, where maintaining a constant temperature is critical. Furthermore, an air conditioner operating at full capacity can save money on avoidable expenses like emergency repair calls, extensive damage to essential parts, and downtime.

What Components Make Up an A/C Gauge Setup?

Most HVAC gauges accessible on the market nowadays contain two readout gauges that jut out from the upper side of a manifold or framework manufactured out of brass. Additional pipes and hoses link to the manifold's base, which is in charge of emptying, testing, and replenishing the pressure inside the Air conditioning unit.


This section of the aircon gauge has three ports, two valves, and three sectors: low pressure, utility, and high-pressure chambers, which are located on the left, centre, and right sides of the unit, respectively. Each of these three chambers has a port for hose connections. When the air conditioning unit requires a system purge, the valves on the two sides control the nitrogen or refrigerant outflow and inflow.

Readout Gauges

A gauge for the low-pressure chamber and another for the high-pressure chamber make up air conditioning gauges. They are colour-coded to distinguish them: red for the high-pressure chamber gauge and blue for the low-pressure chamber gauge.

Low Side Gauge (Compound Gauge)

This section of the air conditioning unit gauge reads the positive pressure in PSIG (pounds per square inch gauge). Simultaneously time, the negative pressure, often known as vacuum, is measured in inches of mercury. Both of these measurements are in comparison to standard pressure. The low side gauge, which includes blue hoses, will show pressures ranging from minus thirty to plus one hundred and twenty PSIG.

High Side Gauge

The high side gauge has red hoses on the right side. It will connect to the HVAC specialist's air conditioning machine's liquid or discharge line port. Low loss fittings or special pair of gloves are required when working with the high side connections to avoid and prevent frostbite. Low-loss fittings may not seem vital on the surface, but they are responsible for minimizing the amount of refrigerant leaking into the atmosphere.


These are critical components of any aircon gauge. That is why they must be rated to handle the pressurized gases that pass through them. Keep in mind that if you want to replace a properly rated hose, such as the one that came with the air conditioner, you should avoid hoses with lower psi values. The yellow lines run from the refrigerant tank to the gauge's utility port to add refrigerant when the AC unit requires it. Adding a valve to this hose is an important consideration since it allows personnel to precisely control the volume delivered into the system.


Precise Aircon Gauges


What method do you use to calibrate the AC gauges?

Before using the two gauges, it's necessary to calibrate them. After you've removed the hoses, open the low and high valves on the manifold to calibrate them. Then, remove the covers that shield the gauge's faces so you can access the calibration screws. After you've finished making your adjustments, softly tap the sides of the gauge to reposition the needle. The needle must come to a complete stop at zero.

What is the best way to add refrigerant?

If you're using a separate thermometer connected to the line by a wire and the temperature reading is higher than expected, you'll need to add more refrigerant. Connect the yellow coloured hose from the utility port to the appropriate refrigerant tank. Next, slowly and steadily open the valve on the low-pressure side of the manifold to add the proper refrigerant until the thermometer indicates the right temperature.

You can see a chart on the compressor cover that shows the relationship between the low-pressure reading as well as the current temperature of the refrigerant running through the line. When the thermometer reads the desired temperature, close the refrigerant supply tank valve, as well as the blue valve on the air conditioning unit gauge. Disconnect the hoses and replace the valve caps as the final step.


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Aircon Gauges from HVAC Shop

When it comes to troubleshooting, maintaining, and fixing heating and cooling systems, HVAC gauges are essential. How a technician works is one of the most crucial things to understand. We hope this article helped answer your major questions about AC gauges in Australia.

HVAC Shop offers aircon gauges from the top HVAC brands in Australia and internationally. We also have experts you can contact for more information.