A/C Installation: Factory Refrigerant for 5m, Adding R410A for 6-7m Pipes, Measurement Accuracy

Leave it as is if the only issue is a 10–20 g dosing error, because on a small split that amount is about 1% of the charge and is smaller than the error from the scale, hoses, and gauges. The factory charge is intended for up to 5 m, and beyond that the manufacturer’s extra charge rule should be followed in principle, but in practice experienced installers adjust by checking the system’s operating parameters rather than relying only on the table [#17267637][#17267646][#17269292] A slight under- or overcharge of a few tens of grams will not noticeably affect performance; the thread notes that serious problems start with much larger shortages, such as local icing, poorer efficiency, or compressor damage when refrigerant loss is significant [#17267646] If a company does add refrigerant, it should charge a bit more and then verify temperatures/overheating and remove or add refrigerant as needed, because the final operating state matters more than the exact theoretical value [#17267637][#17267646]