Blower works, heat cuts out, diag lite blinks

[jgregson]

I have an 8 yr old Amana 80sse furnace that has recently started having an intermitent heat problem.

When the furnace has been on for while and is hot,the flame will cut out and the blower will run continuesly until turned off or the the switch under the lower panel is reset. At the same time the diagnostic light (according to the lower panel) is blinking a "lockout" state.

If I leave the vented top panel off (cooling?) the problem happens less frequently. I haven't checked any of the thermocouples so I can't provide any information there. The only thing I can add is at the time the heat cuts out, everything feels hot. The ducting, the furnace and especially a little blower motor I assume is used to vent any unused gases (if any) out the chimney. The label on the motor indicates that it has a thermal switch in it as well. Questions, questions, I have so many questions...

Thx in advance for any help..

Jonny G

[Action808]

I had similar symptoms ... my heat would cut out, but the fan would stay on until I reset the furnace. The diagnostic LED told me that a Rollout Switch was open. I learned that a rollout switch is something that senses when flames are escaping from their proper area, and forces the furnace to shut off for safety reasons. However, these switches stay in their open state until a person manually resets them. Since I wasn't resetting them, and since the furnace would work again after being reset, it was clear that the switches weren't actually open.

To make a long story short, the control board was messed up, and it was somehow thinking that one of the rollout switches was open when it really wasn't. I had the control board replaced ($300 installed), and it's worked fine since.

I hope that helps.