Performed preventative maintenance for a Lennox furnace model #180uh090p36b-01, serial #5911k10295. The system is located in a detached section of the home. I would call it a play room. Powered the system down and removed and cleaned carbon off the flame sensor. Cleaned out the burners and burner box. Replaced the air filter size 16x25x1. Checked all electrical connections to ensure that they are secure and in good condition. Checked the pressure switch to ensure the is nothing in the hose. I powered the system back up and called for heat. I took a combustion analysis test and got the following readings, o2 is at 9.4, co is at 19ppm. The inducer motor amp draw is at .72 and the blower motor amp draw is at 4.3. The supply temp is at 115°F. The furnace is operating properly at this time. I took a look at the hot water heater. The hot water heater is 11 years old. There are no signs of rust on the connections, the module is in good condition. The water is at the proper temperature. The s