rheem furnace model RGLG-O7NAMGR - Burner does not stay lit

[pophouston]

I have a rheem furnace model number RGLG-07NAMGR - that starts as the flow chart shows that it should but the burner starts as it should but then only stays on for about 1min. I repeats that senerio 3 times and then nothing. The flame sensors seem to be some type of optical devices that I cleaned with a soft cloth. but the problem stilll persists. The fcb led status lights show green.  I'm wondering if i should replace the flame sensors or what other trouble shooting should or might be done

 

thanks

[applianceman18007260692]

Most sensors are metal rods which hang out in the flames. They change in resistance telling the control the flame is lit. Sanding down the sensor helps. Video:http://www.youtube.com/watch?v=I86joWL66aE

Edited January 9, 2014 by Dan Webster

[KCTBURY]

Possibly an air flow problem.  The Evaporator coils may be dirty or clogged filter. Sounds like the high limit thermostat is tripping because too much heat in the exchanger.  

 

Possibly a draft induction problem. Clogged vent pipe or bad induction or pressure switch or tubing to pressure switch.

[applianceman18007260692]

Yeah if the sensor was good I would be looking for an open rollout/limit switch.