Charging Systems with Accumulators
In air conditioning service, we don't always see systems with accumulators. In fact, they are pretty uncommon unless you work on a lot of heat pumps. However, as heat pumps gain popularity, charging systems with accumulators will be a good skill to have in your tool bag. We are Carrier dealers in Florida, so we […]
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Flash Gas
When we say that there is “flash gas” at a particular point in the system, it can either be a bad thing or a good thing, depending on where it is occurring. Flash gas is just another term for boiling. It is perfectly normal (and required) that refrigerant “flashes” or begins boiling directly after the […]
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Is It OK To Top Off With R410a?
I am consistently surprised by how much false information still circulates out in the field, and one of the ones I hear often is the idea that you cannot or should not “top-off” or recharge R410a systems on top of an existing charge of R410a when the system is low. So, to be clear, before […]
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What Should My Superheat Be?
  The most common—and often most frustrating—questions that trainers and senior techs get asked sound something like this: “What should my ______ be?” or “My _____ is at ______. Does that sound right?” Usually, when the conversation is over, both the senior and junior techs walk away feeling frustrated because the junior tech just wanted […]
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Refrigerant Charging Basics For Air Conditioning & Heat Pump Systems
Before I start on this one… At HVAC School, we focus on a wide range of topics. Many of them are very basic. My experience as a trainer for over 16 years has taught me that no matter what I assume others SHOULD know, it doesn't change the fact that they often do not. This […]
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What Should My Subcooling Be?
  This is the article you read BEFORE you call and ask a senior tech what your subcool should be. It's also the one you send to a junior tech when they call and ask you: So, what is subcooling? (Or subcool, as many call it.) Subcooling is a measurement of temperature DECREASE of a […]
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Checking the Charge on a Heat Pump in the Winter
When you ask many people nowadays how to check the charge on a heat pump during low outdoor temps, they will say that you need to “weigh in and weigh out” the charge. While this may be an effective method, it isn't always practical. Now, if you are making a refrigerant circuit repair, weighing out […]
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Know the Limits of Subcooling
This article was written by RSES CM and excellent market refrigeration tech Jeremy Smith. Thanks, Jeremy! I frequently see techs online struggling with charging or troubleshooting refrigeration equipment and using subcooling as a diagnostic or charging method. Please don't do this unless you understand it fully. Many times, trying to charge a refrigeration system to […]
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The “5 Pillars” of Residential A/C Refrigerant Circuit Diagnosis
Suction pressure, head pressure, subcooling, superheat, delta T. Taking all five of these calculations into account on every service call is critical. Even if you must do further diagnostic tests to pinpoint the problem, these five factors are the groundwork before more effective diagnostics can be done. I would also add static pressure as an […]
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