How to Read HVAC Gauges

At Breeze Air Conditioning, we use HVAC tools for nearly every project. We find pressure gauges are critical for most of the work performed on an HVAC system. An HVAC gauge accurately reads the pressure of different gases and liquids in your air conditioning system. Gauges are also vital for charging your cooling system, pressure testing and reading vacuum pressure.

Our instruments will make certain your HVAC system is working correctly. HVAC gauges are important diagnostic tools. They additionally offer convenience for replacing or servicing your unit. We believe HVAC gauges are just as important for our industry as pressure gauges are for the industrial sector.

The HVAC Gauge

An HVAC gauge is ideal for measuring either low or high pressure. Gauges are crucial when our cooling technicians are working on your air conditioner’s evaporator or condensing unit. In order to read an HVAC gauge correctly, our technicians have been trained regarding its basic parts.

Gauge Manifold

We use a gauge manifold for servicing and diagnosing equipment. The component has three chamber devices: the utility chamber, high-pressure chamber and low-pressure chamber. The chambers provide our technicians with control over the pressure and gas. Once the gauge is connected to your device, the pressure levels are read by our technician in your discharge line.

The hose for the high-pressure gauge is connected to the high-pressure side of your unit. Your utility port is what our technicians use to add more refrigerant. We also use this port for the connection of a hose to a recovery unit or vacuum pump. A manifold gauge is critical for servicing your HVAC system by removing contaminated refrigerants from your equipment.

Digital Gauges

A modern digital gauge provides readings for pressure and vacuum using numerals. We find the accuracy better than an analog readout. Since the conversion of the readings is not necessary, the risk of error is decreased. Our technicians are trained to understand the new technology and complicated digital readings.

Readout Gauges

There are two readout gauges in an HVAC gauge to display the high- and low-pressure chambers. Although uncommon, a third gauge is included in specific brands to measure the output of the compressor. The first gauge is the analog readout. The needle position shows the pressure level in your air conditioning system. This is the most common gauge, and it is preferable to the newer gauges since it is simple to use.


Pressurized gas is carried by the hose connection. The hoses are color-coded by the manufacturer to differentiate between low pressure and high pressure. The high-pressure side is red, and the low-pressure side blue. The reading of the red hose is a maximum of 999 psi. The blue hose provides a reading between 0 and 99.9 psi.

Connecting HVAC Gauges

Every HVAC technician is required to know how an HVAC gauge is installed. The job will not be completed correctly if our technician does not make the correct connection. The flexible hoses of the gauge have a connector on each side. To ensure safety, the maximum pressure of the hose is indicated in bar or psi. We have seen many hoses burst due to high pressure when a homeowner attempted to make the repair.

The correct connection must be made for both the ports and the hose. The high-pressure gauges are the red gauge and red port. These are connected together. The low-pressure gauge is blue and connects to the blue port. The blue pressure gauge and lower-pressure side must be connected together with a blue hose.

A disposal hose is required to discharge the unit. The attachment of the hose is placed in the middle of the HVAC gauge. We use a black-pressure hose and recovery bottle for the refrigerant. This is attached directly to the manifold. Federal law prohibits refrigerant from being disposed of in the environment.

The gauge has other ports to attach a micron meter or other gauges. Additional gauge ports are available on the manifold as well. Our technician may require these ports for the connection of a vacuum pump for servicing your unit. The HVAC gauges contain gauges for both temperature and pressure charts. The chart includes a pressure temperature chart, temperature scales and charts for a variety of AC refrigerant pressure.

Exceptional Service

Contact Breeze Air Conditioning today for air conditioning replacement, furnace installation, cooling repair, and HVAC maintenance plans in Palm Desert, CA, and the surrounding areas. We are looking forward to working with you.

Contact Breeze Air Conditioning today!

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