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Tips for Technicians: Pressure Testing a System

Ever been stuck on a tough repair or spent way too long figuring out a system issue? We’ve all been there. This new blog series is packed with practical advice, smart solutions, and hands-on tips you can immediately use to solve problems faster and work smarter. No fluff—just the information that makes a difference when you're out in the field.

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Fieldpiece Liike Gecomprimeerd 00438 Fieldpiece Liike Gecomprimeerd 00438

What is Pressure Testing?

An HVACR technician performs a pressure test on a system to verify there are no leaks before the vacuum is pulled, and the refrigerant is charged into the system. This test is done with dry nitrogen, to ensure the HVACR system is airtight.

This process is used to:

  • Verify system integrity by checking for leaks before evacuation and charging
  • Help purge air and moisture from the system using dry nitrogen
  • Pressurize the system to a controlled test pressure to ensure the system can hold the pressure
Swipe through the steps!

Steps of an HVACR Pressure Test

1. Turn off the system

Prevent injury or damage while setting up for the pressure test

2. Connect the Manifold to the system

Connect the hoses to the condenser’s high side and low side service ports.

3. Isolate the low side

Close the low side valve on the manifold

4. Introduce Nitrogen to the system

5. Increase pressure

Gradually increase pressure to the manufacturer’s recommended level

6. Let the pressure stabilize

7. Hold the pressure for what is needed for the specific system

This can vary from 10 minutes to 24 hours

If the pressure drops, there is a leak in the system. Temperature changes can cause (slight) pressure variations, as pressure drops when the temperature does.

Did the system pass the check? Perfect! The system is now ready to have the nitrogen released and is ready for a deep vacuum to remove moisture before charging with refrigerant.

Did The Pressure Test Fail?

There could be a couple of reasons the pressure test on your HVACR system failed:

  1. Not enough refrigerant in the system due to a leak
  2. Failed component, such as condensor or evaporator
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Fieldpiece Lightzone Liike 08791 min Fieldpiece Lightzone Liike 08791 min

In Summary

Pressure testing is an important step in the installation or troubleshooting of an HVACR system. It is essential to verify that the system does not have any leaks before charging the system with refrigerant. This ensures that the system can run optimally, customer trust, and no callbacks.