Hello,If the light is a steady slow pulse it is "normal waiting"If the light is steady fast pulse it is "In normal heat mode"If the blinks are in sets, that would be a fault code. If you have the model number I can look for a manual for you. The series narrows it down a bit but there are different models within the series.
Do you know where the model number is?
Hello? (I just want to make sure I get you the "right" number. Where should I look for that?
Page 21 here - http://www.trane.com/CPS/Uploads/UserFiles/DXUnitarySystems/Split%20Systems/Gas%20Furnace/18-CD19D7-21_03012010.pdf
Trane and American Standard are the same unit...that is why you will see the model read as *UD.....If Trane it is TUD and if American Standard AUD.
Thank you...page 21..
There is nothing to do because it is "normal" The slow flash means everything is ok....no action necessary
The only difference between fast and slow is if the furnace is running and heating
Slow flash= dormant, everything normal
Fast flash= unit is heating, everything normal
The only time you have issues is if the blinks are in sets of 3...4 etc...
The light would not be solid green...if it were the control would be defective.
The board does not monitor ac...it only turns the blower on. The circuit board is strictly to monitor heat related items. The furnace comes as furnace only...ac is added to it as an option. Therefore when ac is running, the board knows nothing about that at all....all it is doing is running a fan.Do you have an issue that began this situation? or just noticed the light?
Ok, this is not the first time I have had this query..Everyone assumes a blinking red light is bad. But in the case of Trane and American Standard the blinking red light is normal. As you see by the documentation on page 21...the flashing light is normal.In the event the light were solid, that would be a problem. I am afraid I cannot cajole or twist your arm to believe the blinking light is normal......but if you look at the manual you will see it is the case.The fact you changed filter would lead me to check the inside of the blower wheel for any debris, but the circuit board does not monitor that.I am more than happy to further assist you...but in the matter of a blinking red light, that is simply normal.
If you would like I can opt out so the others can have a look.