1 system ac tune up complete. thermostat is outdated, recommend replacing with newer, more reliable thermostat. Changed Filter. Recommend upgrading to 5 inch media filter to help reduce dust in house. Checked mechanical and electrical components, all in good shape. Gave condenser coil a chemical wash and applied rust proof waxing. Insulation on suction line outside was old and breaking down, cut it off and replaced it with new insulation. Recommend surge protection to protect unit from lightning strikes and power surges. System is slightly low on 410a, recommend recharge. Recharged system. system operating at this time.