Help! I having a problem with the flame not staying on. I did some troubleshooting. I have replaced the ignitor and hi-limit thermostat on the assy duct (even through they tested ok). I thought it was the Hi-limit thermostat because when I moved it away from the duct the flame would stay on longer (1.5 min) but eventually did shut off. Both thermostat 1 and thermistor on vent duct resistance tested ok and also Radiant sensor. What am I missing? A while after flame goes out the the timer goes to 1 minute and the "Drying" and "Cooling" lights are illuminated simultaneously on the front panel display. Could t be the gas valve? if so, why the difference in time after moving the thermostat? Could it be the PCB module? its driving me crazy! Please help.