# Carrier Infinity fan always on



## HvacWiz (Nov 24, 2006)

*If you look on the back of your furnace door it should tell you what the switches are for, I think the small red block switches are for settings for the a/c tonage you have the other is for the blower cfm. Cant remember off hand what all 8 are for on the other block, I know switch 4 is for emergency heat, #2 is for bypass humidifier. But none of these will make your fan run all the time. If your furnace is not heating but the fan is working you either have an open limit switch your a blown 3amp fuse on your circiut board.*


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## vcp (Mar 20, 2008)

*Next step?*

Thank you for the response.
The fuse is good.
The furnace heats when needed.
I'll have to ask why there is a difference between the old and new A/C settings and make sure it is set correctly.
What else could cause the fan to run under these conditions?
Thanks,
vcp


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## HvacWiz (Nov 24, 2006)

*Do you have a humidifier, if so what is the setting on your stat, there is an option that will control the operation of the fan motor. Push the humidity button and then you can cycle through the options by pressing the mode button, that is if you have the stat I'm thinking of.*


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## statman (Mar 17, 2008)

Just a question...is the fan switch on your thermostat set to auto?....He may have also connected a speed up to a continuous terminal on your board, if your furnace has one.


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## vcp (Mar 20, 2008)

*Fan always on*

We don't have a humidifier, so I don't think there would be anything there that would keep the fan running. Is there? How would I find out?

The thermostat is set for Auto fan operation. If I turn it to the FAN ON setting it runs the same as under Auto setting.

What other settings or components could cause the fan to run all the time?

Thanks!
vcp


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## statman (Mar 17, 2008)

Either your serviceman hooked up or set up the board improperly , you are getting 24V power on the furnace G terminal or this board is still not working properly.
I dont have your proper M#, etc. but I dug around and found this list of infinity furnaces. Check into the document/ downloads and you may be able to get some help. http://www.commercial.carrier.com/commercial/hvac/general/0,3055,CLI1_DIV12_ETI10505_MID4415,00.html
Hope this helps....if it doesn't, why not just call the serviceman and explain to him what has been happening since he installed the board....should by all means be a warranty situation if he caused the problem.
Hope I can provide some help.


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## vcp (Mar 20, 2008)

*Thanks!*

Thank you for your help!

I'll call and get him out again.

The web site you mentioned was helpful. I noticed that there is a PC based software that allows them to troubleshoot the furnace and it's controller boards. The serviceman didn't use it, but I'll ask about it this time.

Thanks again,
vcp


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## vcp (Mar 20, 2008)

*Fixed!*

The company sent out their best repairman.
The controller board was bad so he replaced it again.
He also set the control board switches correctly.
He told me that secondary controls normally can't harm the main control.
It is running very well now.
Thanks for a great forum!
vcp


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## ro9beam2002 (Jun 6, 2008)

mmmmmmmmmmm


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