Thanks for taking a moment to read - I've reviewed a lot of posts, however still cannot find one that explains why my Interthem G5RC100-16 gas furnace blower will not shut off even after the thermostat has been shut off. I'd also like some help, please, finding the "codes" for the blinking light on the "board" - please?

Look inside the access panels or on the control board housing - you should find a legend to the LED. If you have continuous blower and no heat, a low voltage fuse on the control board has blown, or a limit switch has opened. Check for a clogged air filter.

Thanks so much for the quick reply KC13 - checked (and replaced) the filter, still cannot find the codes, see only one fuse (maybe more?), however the limit switch I am unsure of - is this something I can check? Repair/replace? Thanks again!

You stated that the blower runs continuously, but didn't mention whether the unit was heating. Obviously, there's a big difference between the two conditions. Was the filter clogged? If so, the limit control may be stuck open (usually auto-reset, but not intended for frequent/repeated cycling). Locate it and remove one of the wires. If it has no impact on function or status LED, it is probably the culprit.

Hello again KC13 - and thanks so much for the help! I have done as you recommended, and you were correct: without knowing any more details, I assumed the board was bad, replaced it, and things worked well for the duration of the 2010 heating season. Amazingly enough, however, when begnning the 2011 season, I have a new issue: the furnace will start the cycle, induction motor turns on, ignitor ignites, then a small "false ignition takes place (sounding louder than a regular ignition), the blower kicks on, but the burning chamber has not yet finished completely igniting, so the furnace will blow cold air for a minute or two. Then the process starts all over again - and usually by the second or third try, ignition will complete, and the unit will heat the home. This has been going on for about a week now, and repeats itself almost every ignition sequence. May I please beg humbly for more help please? Is there anything I can replace?

Thank you so much!
Andy
412.302.7002