How To Read HVAC Gauges


When you’re continually handling air conditioning, heating, ventilation, and refrigeration appliances in Broomfield, CO, your HVAC gauges are your most valuable assets. HVAC gauges typically consist of two unique valves connected via a single-spring pressure indication. If you don’t know how to use HVAC gauges, then here’s the guide you’ve been looking for.

What Is An HVAC Gauge? 

HVAC gauges are used to read the pressure of gases and liquids in a cooling unit as well as the vacuum pressure when you’re charging or pressure testing the gadget.

There are a variety of ports on the HVAC gauge set, also referred to as a manifold. The key difference in the types of manifolds you encounter is the pressure that the gauge can withstand and the number of ports through which you can conveniently attach accessories. These factors are essential when you’re working with different refrigerants.

You can also use this device to perform some HVAC replacement and service work.

How To Read HVAC Gauges 

Here, we’ll detail what an HVAC gauge is, what role it serves, and how to read it. But first, let’s take a quick look at the color-coding:

  • Blue: This color stands for gauging the suction pressure of the compressor. The reading ranges from 0 to 99.9 psi and is based on variation in atmospheric pressure.
  • Red: This denotes the time and reads the pressure from the hose. The color boasts a significant amount of utility so that you can know the high pressures rising from the HVAC system.

For HVAC analog gauges, the reading is usually done manually. You can do this by going through the blue and red color-coding labeled on the dials.

Procedure Instructions On How To Read An HVAC Gauge 

Attach the high-pressure side of the cooling unit to the red port on the gauge. The red indicator and the red port are typically the high-pressure gauges. You’ll want to connect a code-authorized red hose designed to tolerate pressure using the flare fittings that come with it to the high-pressure port on the cooling line. Often, the high-pressure port is of a different thread and size than the low-pressure side to avoid the probability of random inaccurate hookups.

Next, attach the low-pressure line to the blue port on the HVAC gauge. Then, connect the low-pressure side with a blue low-pressure hose and the unit’s blue pressure gauge. This will make way for the proper flow of vacuum pressure, also known as a micron meter, to evaluate the vacuum pressure already in the system.

Then, connect a vent hose or waste hose to the middle of the manifold setup. If you want to discharge a system or vent Freon by connecting the unit, you’ll have to connect the bigger low-pressure hose to the center of the manifold port. By doing so, you’ll be able to connect a refrigerant recovery container to the multiple setups to avoid flaunting state regulations regarding the emission of refrigerant into the atmosphere.

Next, connect micron meters or other gauges to the remaining ports. The extra ports on the manifold can be used to attach vacuum pressure (manifold) gauges or even a vacuum pump that can be connected to any piece of furniture so as to perform the appropriate services to the cooling unit as needed for the repair you’re making.

Finally, read out the measurements displayed by the Freon pressure gauges, also called the refrigeration gauges. It shows the pressure in freezing and air conditioning, refrigeration, industrial refrigerators, cold filling equipment, and in cold rooms.

For example, if you have a reading of r22 on the refrigeration gauge and measure 60 pounds, the scales will display 1 degree Celsius (an equivalent of 34 in Fahrenheit).

Quick tip: The refrigeration gauge has the same features as a general manometer but with stricter reading characteristics. It uses a unique weld and is tested to prevent refrigerant leaks. In this manner, you can quickly understand how to read HVAC gauges.

Additional Tips 

When it comes to HVAC gauges and collecting accurate readings, it’s never as easy as buying one set and being done with it. Having two or more sets of manifolds can help you to work on different refrigerants in units and oils used in refrigeration. Fortunately, True Heating & Cooling has all of the information you need regarding the best HVAC gauges for accurate readings. We also provide air quality and carbon monoxide testing. To learn more about how best to read HVAC gauges for your home in Broomfield, give True Heating & Cooling a call today.