Preformed single system heating maintenance on a 2021 carrier gas furnace. The system has 2 zones. I tested all electrical components and safeties. All tested within manufacturer specifications. I changed the filter for the client 20x25x1. I did let then client know they have the room for a 20x25x4 filter so they wouldn’t have to change it as often. Temp being supplied to the home durning a call for heat was at 119.8 degrees and 68 degrees return air. I proceeded outside to visually inspect the outside unit. I did notice the unit did not have any type of surge protection. Unit was heating upon departure.
