Climate Control

HVACR Tech Tip: Basic Troubleshooting Given Three Measurements

What if you are only given 3 measurements?

As HVACR technicians, you need some ideas in your back pocket for basic troubleshooting in a refrigeration system. How about a simple chart that helps you diagnose a system with 3 data points for starters?

Let’s take the following 3 data points as an example; compressor discharge pressure, suction gas pressure and suction gas temperature with the latter 2 being taken at the evaporator outlet. Calculate superheat using the suction pressure and temperature. Using compressor discharge pressure, suction pressure and superheat we can compare to normal condition, lower than normal, or higher than normal.

To simplify this analysis, you will assume the system components, compressor, evaporator, condenser, and expansion device, are properly sized and the equipment is sized correctly for the original load.

For each of these combinations, you may assume the expansion device to be either a TEV or fixed restrictor, whichever you believe better explains the problem. See chart below for basic troubleshooting.

HVAC Tech Tip: Basic Troubleshooting Given Three Measurements - Chart with various troubleshooting paths - Parker Sporlan, Parker Hannifin

Using this chart is simple and can greatly speed up the troubleshooting of a system. Other tools that can speed up your diagnosis is the SMART Service Tools that connect quickly and easily to allow you to get fast and accurate temperatures and pressures delivered directly to your smartphone or tablet. And, the ChillMaster P-T app readily converts all common and many uncommon refrigerant pressures or temperatures to the other for easy superheat or subcooling calculation.

 

Use of Suction line filter driers for clean-up after burnout of HVAC systems - Glen Steinkoenig Product Manager Contamination Control Products, Parker Hannifin Sporlan Division Article contributed by Glen Steinkoenig, product manager, Thermostatic Expansion Valves, Sporlan Division of Parker Hannifin

 

 

 

For more articles on climate control:

Using P-T Analysis as a Service Tool for Refrigeration Systems

HVACR Tech Tip: 12 Solutions for Fixing Common TEV Problems

HVACR Tech Tip: Where Should the TEV External Equalizer Be Installed

Compressor Overheating Is the Number-One Refrigeration Problem

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