On arrival, I found the system completely flat on refrigerant. I had to add refrigerant into the system to be able to run my electronic leak detector across the coil. Did find a leak at the service valve of the outdoor heat pump. Also inspected the indoor coil and found the coil to be extremely rusted and corroded. I recommended to the homeowner that we replace the indoor coil, replace the outdoor valve and recharge system back to factory specifications to return to 100% cooling and heating capacity. I also recommend installing our Stage 1 & 3 Breathe Easy Packages to keep the complete HVAC system clean, as there are signs of microbial growth inside the indoor air handler. Installed new indoor coil and rebuilt and insulated condensate drain. Also installed Stage 1 & 3 Breathe easy packages. Replaced the outdoor valve and charged system to factory specs. System is working properly at time of departure.