Performed furnace maintenance on a Lennox communicating gas furnace in Calimesa. Units heating temperature split is in range. Filter is dirty and replaced today with a new MERV 16. Sensors and switches were cleaned and tested. Gas valve and ignitor were tested and recorded. Duct runs are sealed. Condensate lines are clear. Electrical amp draws are all within range meaning an electrically healthy system. Indoor unit is not protected, which is cause for concern if the goal is to get the maximum out of years out of the system. Condition was discussed with the homeowner. System is operational at end of appointment.