How to Use HVAC Gauges?: Take Readings Properly (Updated Guide)

People who work with air conditioning, refrigerator, and other such electronics know just how important HVAC gauges are. These gauges help read pressure, and you must know how to use them to get the right reading and troubleshoot accordingly.

In the market, you may find what are popularly called manifold gauges. These are sets of HVAC gauges, and they have different ports. There are numerous such gauges, with the main difference being in the number of ports. Another difference is in the withstanding capacity of the gauges. Not all gauges have the same pressure capacity.

How to Use HVAC Manifold Gauges?

Let’s take a deeper look at AC gauges and how to read them:

A brief about AC gauges

Each AC gauge has three main ports: (From right to left) High pressure chamber, utility chamber, and a low pressure chamber. You can also identify the chambers by color. High pressure gauges are red, and low pressure gauges are blue. The ports reflect the color code as well.

The working of AC gauges is pretty straightforward. The main focus is usually on the hand valve, the opening and closing of which changes everything. On the AC assemble you will see a needle along with a small port. To open the hand valve you have to rotate it clockwise and to close it, you have to rotate it counterclockwise. This mechanism holds true for low and high pressure ports.

Which way to go? Analog or digital?

While analog gauges are age old, they are being overtaken by digital AC gauges quite easily. However, even today, many technicians use analog gauges because they are comfortable and understand the readings quite easily. In fact, expert technicians don’t even need a chart to understand the readings. There are shortcomings as well, though. It is easier to make errors with AC gauges. Conversion errors and errors in reading are quite common.

Digital gauges, on the other hand, are much easier to use and the accuracy is unbeatable. However, many technicians shy away from these because they need to understand the technology and be trained in the same. They find it complicated mainly because features differ based on the brand and it is hard to keep up.

Calibrating analog AC gauges

To get the right reading, it is imperative to calibrate the AC gauge. Otherwise, the readings will quite obviously be wrong.

1. First of all, you must remove the hoses from the chambers.
2. Then you should open the low and high valves of your AC manifold gauge.
3. Once you remove the protective covers of the gauges, you will see calibration screws.
4. Make your required adjustments with these screws and tap the sides to change the position of the needle accordingly. It must be on zero.

A few usage tips for you

As aforementioned, the high pressure side is attached to the red port and the low pressure side is attached to the blue port. Further to this, you may find the following tips very helpful:

1. The center part of the manifold is where the waste hose is attached. You may also call it the vent hose.
2. Besides the three main ports, you will see additional ports that come in handy when you want to attach micron meters, vacuum pump, and other similar gauges.
3. You may need more than just one set of HVAC gauges to get the work done. Many professionals carry at least two with them.

There you have it! This is a simple guide on how to use HVAC gauges. If you have any doubts or would like to share a few points, we would love to hear from you!