I installed a WaterFurnace Series 5 system ( 6 ton system with 2 units ) about a year ago. Everything is working great so far. Glad to be off oil. Savings are significant. I am wondering if there is anything I need to do to maintain this system or what is entailed in a maintenance checkup? I keep reading that there is very little maintenance if any. I change the filters myself every 3 months. ???