Came out to remove furnace and coil, shut off gas, pumped down condenser refrigerant. Disconnected hot water tank and furnace gas lines. Disconnected furnace pvc. Removed system and found that not much more sand had come into system since last weeks job. thoroughly removed as much sand from plenum as possible with shop vac and sepecialized wands. Found several rusting out stress points and 3 openings in plenum allowing sand in. Sealed openings and reinforced stress points with sheet metal, mastic and concrete. Poured in a solid concrete foundation as far back into plenum as possible. Reattached plenum hardware components and replaced system. Reattached refrigerant, gas and plumbing lines. Vacuumed system down, since it is an Amana we did not replace the filter drier. Vacuumed down to 400 microns. Relit hot water tank and tested and verified proper function. Pressure tested and started furnace and air conditioner. Tested and verified system is working properly form thermostat. Checked r