I arrived for a club member fall maintenance. I spoke with the homeowners and for that they are not having issues with the furnace or ac system. I inspected the furnace and for the system to be running. I cycled the system off and checked all electric components and cleaned the flame sensor. I then cycle the system on and checked gas pressures amp draws and temp rise through out the home. I found one room with a 6 deg temperature difference through the vents. This is the only room with round vents and they are located in the cycling vs the wall stub out like the other rooms. I recommended to replace the fuse due to the age of the system. The homeowner wants to run the system for as long as they can.