Furnace has a mind of its own, and it's stubborn and hard headed.
My rheem criterion II Gas furnace model# RGPH-07EAUER is give me some problems. All right first off it wasn't turning on when the room temp. Was below thermastat setting so I then tried turning the thermastat off waiting a couple minutes. Then turning back on. Well the furnace started it's cycle then I went to see if the igniter was working it wasn't so I then turn everything off and use some sand paper on the igniter and then turn it all back on, well the igniter work and the burners kicked in, but only for a minute. So I then turned everything back off and sanded on the flame sensor, then turned it all back on and it worked for a day then same problem happen again so I change the igniter with a brand new one turn the furnace on and the igniter worked but the burners cut back out after a minute. So I then sanded the flame sensor again and the furnace worked for a day again turn it's self on and off like it suppose to. The next day woke up to a cold house furnace not working, the brand new igniter not working, I'm thinking I need to change the flame sensor or some other sensor I just don't what sensor or what to do?