Tips for Technicians
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.
The Importance of Correct Refrigerant Charge
Getting the refrigerant charge right isn’t just good practice — it’s essential to the performance, efficiency, and reliability of every HVACR system. Whether you're servicing air conditioning units running on R-32 or handling a refrigeration system using R-134a, the rule is the same: the system charge needs to be accurate. A properly charged system runs more efficiently, keeps temperatures stable, and protects the compressor from unnecessary stress. An incorrect charge, on the other hand, can lead to poor system performance, excessive wear, and even premature failure.
How Undercharging Affects System Performance
Overcharging or undercharging an HVACR system does not just impact the performance of your system—it will also actively damage the system’s components and ultimately lead to costly failures. When a system is undercharged, it lacks the proper volume of refrigerant needed to absorb and move heat efficiently. This will result in poor cooling or heating performance as the evaporator cannot reach the temperature required to facilitate the needed, required heat transfer.
Undercharging can also place significant stress on the compressor. Read more about the importance of the compressor in an HVACR system in this blog. With an insufficient amount of refrigerant returning to the compressor, the pressure on the suction side will drop. This can cause the compressor to operate at higher temperatures, increasing the risk of the compressor overheating. One of the more dangerous outcomes of an undercharged system is the freezing of the evaporator coil. As the pressure and temperature drop too low, moisture condenses and freezes on the coil, eventually blocking airflow. Once airflow gets restricted, pressure starts to build up, and the compressor has to work much harder, pushing the whole system further away from the operating range.
Why Overcharging Can Lead to Total Compressor Failure
On the other hand, overcharging a system can be just as damaging and comes with its own set of problems. With too much refrigerant in the system, pressures throughout the circuit rise. This elevated pressure forces the compressor to work harder than necessary, increasing energy consumption and reducing overall system efficiency. Over time, the strain can lead to compressor overheating, damaged valves, or even mechanical failure. Unlike undercharging, which often presents slowly over time, overcharging can sometimes lead to immediate shutdowns if high-pressure safety controls are triggered.
A particularly harmful result of overcharging is liquid refrigerant making its way back to the compressor — a phenomenon known as liquid slugging. Compressors are designed to compress gas, not liquid, and when liquid enters this component, it can cause internal components to break. This kind of failure is catastrophic and typically leads to total compressor replacement.
The Charge Must Be Precise
Whether the system uses R-134a, R-410A, or any other refrigerant, the core principle remains the same: the charge must be precise. Both undercharging and overcharging push the system outside of its designed balance, leading to inefficiency, increased wear, and higher risk of failure. Accurate charging, supported by proper tools and methods, isn’t just a best practice — it’s critical to system health and long-term performance.
At Fieldpiece, we design tools that help technicians like you charge systems right the first time. Whether you're diagnosing a tricky system or ensuring peak performance on every job, our precision instruments make your work easier, faster, and better.
Stay tuned for more Tips for Technicians to help you tackle the toughest field challenges.