# Rheem RGFD Furnace Flashing 66 LED



## sneaky_pete (Dec 27, 2007)

I have a Rheem RGFD modulating furnace and it is displaying a flashing 66 LED code. If I read the owner’s manual correctly, I think it’s saying that this is a “blower operating over RPM limits” code, with many different possible causes/solutions. I’m having problems with my installer, in fact I can’t as of yet even get him out to look at it. On the phone he said, “oh, that means it’s 66% burn” – whatever the heck that means. I think he’s trying to say that since this is a multi-stage furnace, that it’s operating at 66% capacity, but I don’t think that’s what the LED is saying. I guess I’m looking for advice in two areas – first, anyone have experience with this type of furnace and that type of code, and second, what should I do about this installer? The unit is still under warranty. Thanks very much for any ideas.


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## coolmen (Apr 11, 2006)

page 81 in your furnace booklet explains the codes and possible causes to this as well as solutions. first and formost is check the airfilter. probable causes.... A. ecm motor operating at rpm limit. B. unit installed in a normall extreme. how long has it worked without any problems? 

dirty filter
inadequate return air supply
undersized ductwork
loose blower wheel
filter type to restrictive,


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## sneaky_pete (Dec 27, 2007)

Thanks for the reply coolmen. I checked the filter first and it was very clogged, so I thought "Aha...bet that's it" - no such luck. Still a flashing 66. It's done this since being installed - this is a new construction house. The rest of those solutions I need help with, and therein is my other problem - my installer doesn't think there's an issue. And maybe there isn't - as you say, one of the causes is being installed in a "normal extreme" environment. I am in Denver, so high altitude - maybe he didn't install the high altitute kit? Not that I even know what that is. I think I'll just have to force him to look at it, and maybe as an inspection contingency before closing on this property I require a written document saying he's checked it out? What do you think of that strategy?


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## bigMikeB (May 31, 2007)

I would call Rheem customer service and explain the situation and have them reccomend a service contractor in your area and have that guy come out, they should help you out with this as it is under warranty.


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## sneaky_pete (Dec 27, 2007)

Thanks bigMikeB. I'll give the installer a chance to correct or explain and then escalate if needed. Just wasn't sure if this was a common code or not in these units.


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