My wife called me yesterday to inform me that we had no heat in the house. Once I got home (7:00AM), I checked everything and sure enough... it doesn't work! So my Rheem Classic 90 Plus furnace is malfunctioning ... what to do. The LEDs inside the furnace indicate that the "Limit Switch is Open"... whatever that means. I looked up the problem on the Al Gore invented Internet after I woke up (3:30PM) and sure enough.... something is wrong with it. :) If I can't figure this out tomorrow, then I guess I will need to call the heating and air people for service. On the bright side, at least I won't be using up our precious propane. It also makes me feel great to know that we are no longer destroying the Al Gore protected environment with my pesky CO2 gas.