Today the A/C that had a refrigerant adjustment last summer and a new evaporator coil installed the year before last summer had a very low charge that is preventing it from cooling properly. I met with Michael after I arrived and he led me to the indoor furnace and evaporator coil. The indoor coil was accessed and checked for signs of leaking. There was no oil present at the indoor coil as well as the thermal expansion valve. The coil was then wetted and checked with a leak detector. The coil did not present any leaking. I then checked the rooftop condenser and discovered refrigeration oil at three different places 1: on the line-set at the first elbow, at a condenser coil u-bend and at the service valve. The unit has been flat and pulls below atmosphereic pressure which allows outside air into the system. While on-site it was discovered that the flue pipe for the furnace and the hot water heater has rusted through and has several large holes as well as split seams at the