Arkansas HVACR NewsMagazine March 2021

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• Piping Diagrams : Below, you’ll see a typical piping diagram shown in a service manual. These can be helpful tools in troubleshooting an issue. Note that the red arrows indicate flow direction during heating operation and blue for cooling operation. The upper line coming into the four-way valve is always discharge gas, and the middle line coming out of the four- way valve is always suction gas. This unit’s EEV is also located in the outdoor unit, meaning the lines leaving the outdoor unit are the expansion line and the gas pipeline.

it will show you an OL even though the thermistor is n’t actually open. Instead, it’s just a value that’s higher than what your meter is capable of reading. If you’re unsure, check the spec sheet for your respective meter. Make sure you have a nitrogen regulator that is capable of 600 PSIG. That way, the proper pressure test can be performed. I also recommend having a good thermometer that’s capable of reading pipe temperature.

COMMON ISSUES

Let’s touch on a couple of things that could very well help you out if you are on a mini-split call. 1. Leaking Flares : Leaking flares are among the most common causes for a service call and one of the easiest to avoid. Using a good, sharp blade on your tubing cutter, deburring the copper, making a proper

Tools Required : If you are going to work on mini-splits, there are a couple of items that you MUST HAVE. A good multimeter that can read a high resistance is an ABSOLUTE MUST HAVE. Most thermistors’ values are 5 -75K ohms. If you do not have a meter capable of reading that high of a resistance value,