14yo Carrier / United technologies geothermal R410A puron two stage 5 ton system is locked out on low pressure switch due to a complete loss of all refrigerant in the system. Pressure is at zero upon arrival. Nitrogen pressure test at 480 PSI discovered a rotten away indoor air coil. Die staining is visible in multiple areas but the nitrogen pressure test has discovered non-reparable leaks within the cooling fins of the coil. System needs the indoor air coil replaced, liquid line filter dryer, 144 oz new R410A, oil dye conditioner, 80uf capacitor, ground loop repressurize Seth will contact local distributor regarding repair parts and prepare estimate as soon as possible.