When I arrived at system, I was told heating didn’t work. I started with turning on thermostat to heating mode. I didn’t hear system kick on at all. I went to furnace cabinet and saw error code. Pressure switch fault was issue, rodents chewed through pressure switch tubing. Tubing had a hole in it and it was preventing system from turning on. I cut back tubing and attached back onto pressure switch. System turned on in heating and system operational. Then I started with maintenance to furnace. I cleaned flame sensor of all corrosion. I inspected blower motor and blower motor is dirty. No gas leaks to system, and gas turned on. The ducting had holes in it from rodents. I replaced air filter with one that tenant provided. Registers reached up to 110 degrees out of all vents. The system is operational upon departure.