lennox whisper heat g20
Whisper heat models light the pilot light first then the pilot is proved by the sensor which reports back to the ignition control (grey or blue box on right hand side). A common problem is the spring on the left hand side of the damper that makes a little end switch to allow spark to the pilot. The spring arm breaks and the pilot doesn"t light. Since your pliot is on, probably a dirty sensor (but then you typically hear it trying to spark ignite for a long time) check power going to gas valve or not. Could be ignition module or gas valve at that point.
Last edited by HVACDave; 10-03-2011 at 03:02 PM.