Can you add 410 to a system that's low

You can add refrigerant to nearly all compressors if you have the correct equipment. How to Add R-410 Refrigerant | eHow.com Be sure you are doing correctly and that the equipment is definitely already r410a

As Bob said, yes you can top off a 410a system, no problems. However, if there is a leak, the leak needs to be found and fixed before recharging