# 4 red flashing lights



## Doc Holliday (Mar 12, 2011)

Cut n pasted this:

The general error flash codes for the majority of the Freedom 90 series shows 4 flashes as an "open temperature limit circuit". There are a number of limits on furnaces and they need to be checked to see which one is open. There is a thermal cutout that is auto reset and two flame rollout sensors that are usually manual reset. They are all on the same circuit and usually are connected by yellow wires. If it is one of the flame rollout sensors then there will be a small button to press to reset it. If it is an auto reset limit then cycling the power off and back on to the furnace will clear the code and allow the furnace to start again. If there is a real problem the limit will trip again and lock out the furnace.

The reason limits usually trip is that there is not enough airflow in the system. This is usually found to be a dirty filter, dirty indoor coil, or too many air registers closed down or blocked. Check all these and if the problem is still there, get back to me with the full model number of your furnace - it is located in the compartment with the burners.


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## Mongiovi (Nov 21, 2011)

All of the registers are open, and I replaced filter, what is the indoor coil? Just incase here is the model # AUY120R9V5V3 serial # R465SJL7G I appreciate your help!


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## Doc Holliday (Mar 12, 2011)




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## harleyrider (Feb 20, 2007)

back around the 2001-2004 era, Trane and American Standard had a bunch of bad boards that would give a false code 4. If you can't find a good reason for the code, I would be suspect of the main board. Now on the other hand if you find an open limit then the board is OK.Limits open up from lack of air flow and flame roll out.


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