Upon arrival for double tune up I asked homeowner to show me to thermostats and access to indoor units I then asked for filters to replace which he started that he had them available in the attic, Lastly I asked for a container of vinegar which he provided I went into attic to begin tune up, started with checking temperature deltas, units had a 21 and 22 degrees of cooling I then replaced filters on each unit I then checked blower fans and both were clean and in good condition Checked evaporator coils and both were clean and in good condition Then checked and tightened electrical connections that were loose Lastly I checked drain lines, poured vinegar down the line then chased with 1 gallon of water each and had no backups I then moved to outdoor units, I checked safety disconnects, both in good operating condition Removed both condenser fans and checked, both are in good condition Cleaned coils from the inside out then rinsed off the sides to clear debris. Replaced condenser fans