A refrigerant charging scale is a precise electronic platform used to weigh gas as it is added to your Heat Pump System. This is the only way to ensure your system has the exact charge required by the Technical Data. Because our Multi-Zone units are very sensitive to the amount of gas, "guessing" can lead to poor performance or compressor failure. A digital scale allows a EPA 608 Certified tech to add gas down to the tenth of an ounce. This accuracy is what ensures you get the full SEER2 Efficiency you paid for. If you are a pro looking for high-quality gear, check our Become a Vendor page. It is a critical tool for any custom Line Set installation. Using a scale is a hallmark of a Professional Grade installation.