# American Standard Freedom 80 LED Light Blinks 4 Times



## robertlmills

Hi,

My furnace was coming on and then the burners were turning off after 5 minutes and the LED was blinking 4 times. I found the codes and wiring inside the panel and it says that it is the "high limit device". I changed the device in this picture and now here is what happens.

When I have my thermostat set below the current temp I have a nice consistent slow blinking light. When I turn it up above the current temp, the fan comes on, but now my burners do not come on at all and the LED is blinking 4 times. Any thoughts?

The furnace model# ADD100C945D0

Thanks, Rob


----------



## harleyrider

a high limit is a safety device installed in your furnace to keep you from burning your house down. It is located in the air stream @ the heat exchanger. When the limit trips or "opens" it means that something is restricting the air flow. The most common culprit is a dirty filter and or a dirty evaporator coil.


----------



## robertlmills

*Changed the air filters*

You were helping me on my other thread. Thank you.

The filters were the start of the problem and have been changed. I have no idea how to find the coil. If I took a picture of my furnace, could you help me?


----------



## robertlmills

*Furnace*

Attached are the pictures of the full furnace with the covers on, the bottom section with the cover off and the top with section with the cover off.

Again any help letting me know where the coil is that I would need to clean is greatly appreciated!


----------



## Houston204

That looks like a downflow furnace, the evaporator coil (used for cooling) would be below the furnace if it is present.

Have you reset the power switch to the furnace after replacing the dirty air filter?


----------



## harleyrider

there is one thing i want you to look at......you have a counter flow furnace.....in other words the blower is at the top and the burners are at the bottom,I have seen many many many MANY times were on Trane and American standard counter flow furnaces were the glue that holds the blower compartment insulation is sub par, it dries out and the insulation gets sucked up against the blower on both sides......causing limits to trip....there are limits or i should say, there is a limit in the blower compartment on your unit..I cant see into the blower area in the pictures that you have posted. If its not an issue then you will need to access the evaporator underneath the furnace and see if It is plugged. What part of the country do you live in if you don't mind me asking?


----------



## yuri

there is a secondary limit mounted on top of or the back or side of the fan housing and it may have a red manual reset button which needs pressing.


----------



## robertlmills

*Probably about as far as I can go*

@HarleyRider: I'm in Oregon and starting to wonder if I am as far as I can go. Under the furnace is sheet metal held together with screws, but things are coming out and sealed off. I'm probably going to have to call another professional. I'm avoiding it because the first one that came out changed a filter and charged me $120 and obviously didn't correct the problem.

As for a reset button, their isn't a visible one on the outside of the three sides I can see and I can't get to the back since it is flush against the wall.

Is there another picture that I could take and post that might give me a chance of not having to call someone?

Again, I appreciate all of the help.

Rob


----------



## harleyrider

robertlmills said:


> @HarleyRider: I'm in Oregon and starting to wonder if I am as far as I can go. Under the furnace is sheet metal held together with screws, but things are coming out and sealed off. I'm probably going to have to call another professional. I'm avoiding it because the first one that came out changed a filter and charged me $120 and obviously didn't correct the problem.
> 
> As for a reset button, their isn't a visible one on the outside of the three sides I can see and I can't get to the back since it is flush against the wall.
> 
> Is there another picture that I could take and post that might give me a chance of not having to call someone?
> 
> Again, I appreciate all of the help.
> 
> Rob


 
in the bottom picture is the blower area......turn off the power, remove the circut board and mounting bracket, then remove the flue pipe. You will be left looking at the cover to the blower compartment, remove that and then you will be looking at the blower. On either side of the blower is insulation that acts as sound deadening material. Is this firmly attached or is it "flapping in the breeze"? If it is lose remove it by removing the two screws from the out side of the cabinet, this will release the two 1" strips of metal that was keeping the insulation from getting sucked all the way into your blower. Now look for the limit(s) in the blower housing and ohm them out to see if they are open or closed.

Let me know what you find.


----------



## robertlmills

*Will look in the next couple of hours*

I will look in the next couple of hours and post back.

THANK YOU!


----------



## robertlmills

*Picture of what I have found*

I removed the circut board and mounting bracket and then remove the flue pipe. The attached picture is what I am now looking down at.

I didn't find any insulation or the limit(s) in the blower housing.


----------



## harleyrider

I more panel.......your almost there !


----------



## robertlmills

*I'm in!*

It looks like I am in and the insulation is fine (see picture). In the other picture, is that the limit in the blower housing I need to check?


----------



## harleyrider

yes the insulation looks good,the only way to check that limit is with a meter or a continuity tester, how about the insulation on the other side of the blower?


----------



## robertlmills

*Next step*

The insulation on the other side looks the same. 

I went and got a meter. When I put the meter on the new other limit part it comes up zero. When I put it on this part it comes up with a number larger than 0, but I don't know what to put the tester on. It has options for 200, 2k, 20k, 200k, 2m under OHM.


----------



## yuri

You can *TEMPORARILY AND I MEAN TEMPORARILY* jumper it out to see if it is the problem. It may be partly/lightly/weakly closed. Should have 0 ohms resistance if closed.


----------



## harleyrider

doesn't matter what scale its on.....just ohms is fine, then touch the leads together and observer what the reading is......now with the two yellow wires OFF the limit, touch 1 lead to each tab on the limit at the same time.....the results should be the same as when you touched the leads together, if not then the limit is tripped. remove the limit and smack it down on a hard flat surface and check it again. Also check you private messages.


----------



## robertlmills

*Eureka!*

I love the fact that "smack it down on a hard flat surface and check it again." was the solution. Thanks for all of the help! Do I have to worry about the part that I slapped on the concrete?


----------



## harleyrider

robertlmills said:


> I love the fact that "smack it down on a hard flat surface and check it again." was the solution. Thanks for all of the help! Do I have to worry about the part that I slapped on the concrete?


 
Only if you dont keep your filter changed on a regular basis, BTW we call that "tricks of the trade"......glad its working.


----------



## scoooby

Just spent $123 to find out the 4 light flash was a $15 replacement part! It was the capacitor that sits on top of the blower housing. Just remove the filters and it's located on the top left side. Hopes this helps someone in the future!


----------



## scoooby

Just spent $123 to find out the 4 light flash was a $15 replacement part! It was the capacitor that sits on top of the blower housing. Just remove the filters and it's located on the top left side. Hopes this helps someone in the future!


----------



## Rixsite

Harleyrider's "smackdown" solution worked for me too. You just paid for my cocktails last night my friend - - THANK YOU VERY MUCH!


----------



## punchycool

harleyrider said:


> Only if you dont keep your filter changed on a regular basis, BTW we call that "tricks of the trade"......glad its working.


I am seeking help with this problem, kind folks...I found and pulled the high limit switch. I have the same unit described here. It ohms out, so it's not tripped. I did the ole bang job with the switch a few times on the workbench for god measure. I reinstalled the switch. Still, I got 4 flashes.

I then bridged the terminals together, and powered up the unit for 5 sec, and then off. I read a few places that this should reset the system when this occurs. And yes, my filter was terribly dirty...shame on me, yes. I then removed the bridge I created between the two terminals. I let the system sit for 5 min OFF. Then, I powered the system up again. And again, once the system comes up, the burners come on as usual, but no fan (same as all the other times). And I still get 4 flashes.

Could this high limit switch have truly taken a dump? The unit is 10 yrs old. I also have a 10 yr old heat pump attached, but I don't believe from reading that this has anything to do with my problem. I don't get an AUX Heat warning on my thermostat, so it's never getting up enough to activate the heat pump. Any other help out ther :yes:?

-paul


----------



## jagans

Look at the amount of dirt on surface of the inducer fan. It appears that the filter was neglected for a long time on this furnace, and a general overall deep cleaning is needed, including removal of the main blower motor and wheel, the burners, etc. etc.

Until its clean, how can you diagnose anything?


----------



## Marty S.

No fan is your problem. Need to check if the control board is sending 120v to the motor or not


----------



## punchycool

jagans said:


> Look at the amount of dirt on surface of the inducer fan. It appears that the filter was neglected for a long time on this furnace, and a general overall deep cleaning is needed, including removal of the main blower motor and wheel, the burners, etc. etc.
> 
> Until its clean, how can you diagnose anything?


It was only 6 mos between filter cleanings...long, but not an eternity. My unit has four filters - two traditional screen types and two electrostatic units. Yes, very dirty. But, the inducer fan is very clean as is the blower wheel. Already checked all of that. Burner area and heat exchanger are clean as a whistle.


----------



## punchycool

Marty S. said:


> No fan is your problem. Need to check if the control board is sending 120v to the motor or not


Hmmm. I'll check that in 30 min and report back...


----------



## punchycool

punchycool said:


> Hmmm. I'll check that in 30 min and report back...


OK, power is confirmed at the blower motor...I'm getting 120V...


----------



## punchycool

I have two limit switches, of sort. One enters the combustion area of the burners and has the two-prong 4" long probe like the one pictured above in this thread. The 2nd limit switch enters the blower case and rather than the two-prong probe style, it is just a short 1/8" button probe. For the life of me, I cannot figure out which one is the "high limit switch" that seems to yield the 4 LED flashes I'm getting. I can tell you that both probes are very clean, and both have continuity (they're not open) no matter how much force I exert on the probes (they're not worn out inside is my point).

Any other ideas friends?


----------



## punchycool

I found that the old high limit switch was intermittently going to 'open'...so I found a replacement, new Trane part, but the problem persists - same 4 flashes. Any other ideas? Is there some area of the combustion section that sucks air into the system that is blocked somehow...that's what I'm starting to research at this hour. I just think that the switch is hitting 200 deg and tripping. My blower motor does not run...I'm guessing that the system must exhaust any CO2 prior to kicking on the blower to feed the registers, and since the chamber gets super hot, it shuts off. Hmmmmmmmm....


----------



## punchycool

OK, I think I was chasing my tail...

Sending a call for heat or just turning on the fan from the thermostat produces no fan at all. My problem has to be the fan like was suggested above. The lack of fan is making the heat chamber and exchanger too hot and turning off the system...it's gotta be. And some research shows I have a variable speed blower. Both elec connections on the blower are good. Yikes, this thing doesn't look cheap. And I just hit 10 yrs old on this system install this past Oct (2012)...darn. I need to get someone out to see if it's the blower motor or the module on the end of the motor. I may try to yank it tonight and then take it to a servicer for testing in the morning.


----------



## Doc Holliday

Don't do that. Have a tech come out but let them know it's a variable speed ecm motor. They should have a tool specifically to test the motor or you can simply purchase one and test it yourself. You can leave the motor installed in the unit. 

They come relatively cheap to in the hundreds. 

Cheap.









Expensive.


----------



## punchycool

Doc Holliday said:


> Don't do that. Have a tech come out but let them know it's a variable speed ecm motor. They should have a tool specifically to test the motor or you can simply purchase one and test it yourself. You can leave the motor installed in the unit.


Thank you, Doc. I'll get someone to my place in the morning.


----------



## Doc Holliday

Sure thing. Most likely it'll be the module.There's a known resistor on the board in there that's known to fry on those things. 

Let us know.


----------



## punchycool

Doc Holliday said:


> Sure thing. Most likely it'll be the module.There's a known resistor on the board in there that's known to fry on those things.
> 
> Let us know.


Interesting twist...see this thread, post #25, 26. It's not that I purposely ignored Doc ;-), it's just that I cannot find an available tech this weekend with know how to test my ECM motor...so, I kept digging here on this site, and digging and digging. Very impressed with folks here and the great detail found. 

Do, check out my current status here.

http://www.diychatroom.com/f17/variable-speed-trane-blower-motor-117160/index2/#post1092691


----------



## jkedwards

*Thank you harleyrider!*



harleyrider said:


> doesn't matter what scale its on.....just ohms is fine, then touch the leads together and observer what the reading is......now with the two yellow wires OFF the limit, touch 1 lead to each tab on the limit at the same time.....the results should be the same as when you touched the leads together, if not then the limit is tripped. remove the limit and smack it down on a hard flat surface and check it again. Also check you private messages.


harleyrider saved me at least $100 with his answer. The switch was stuck open so I gave it a whack and fixed the high limit switch right up. Now we have warm air again - in time for November's cooler temps! Thank you so much harleyrider!


----------

