# 3 - flash code, american standard freedom 90 furnace



## dfferg

Its late August, thought I'd check out the american standard freedom 90 furnace. It worked fine last spring, but now flashing 3, for a "pressure switch error". 1) furnace does not even start up, but it has power. 2) hoses from two pressure switches, as wel as the rest are clear, no water present. Question, what pulls (or pushes) air flow to engage pressure switches? That seems to be the initial problem. Turn thermostat up, flashes normal - call for heat. Then it goes directly to 3 flashes. What to do? Thanks!


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## murray

I think the pressure switch is an air proving type ,the switch senses that the power vent fan is running ,if it does not sense a negative pressure it will go to error .check the other end of the tube where it hooks up to the draft assist fan clean it up ,turn the power off for a few minutes then turn it on .the draft assist fan should come on for 30 sec or so ,if its good the burners will fire ,then a minute or so later the blower will kick in .If not ,it would go to error,the draft assist fan will run for a few minutes then shut down and will not reset without turning the power off and on again .I bet a bug crawled in it  If i,m wrong please someone post it ,I would like to know if my old wisdom is any good still


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## Tony

Murray,
I was having this same problem, and upon looking it up I found your post. You were EXACTLY right!!! A bug had crawled into the tubing feeding the pressure switch, and had made a little nest of sorts in it. I used a small wooded skewer and cleaned it out, reinstalled the tube, and VOILA! I have heat again! Just wanted to let you know that your wisdom is still great!  Thanks!!


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## Dennis

if the gas is not turned on you will get the same 3 flash reading also.


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## portclinton

I had this same problem this morn and removed the front cover. noticed that there was water in the small flex tube going to my pressure relay. I removed all the water. (took a couple of tries). Then replaced bottom cover. I then started furnace and blew into the hose. I noticed that the heating element started to heat. Has been working fine for about 3 hours now. Will keep you updated.


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## jackley

*American Standard 90*

I just wanted to reconfirm this fix. My problem was calcium type build up. I cleaned what I thought was all the hoses but did not check the easiest one from the main unit housing to the relay unit. The build up was in the hard plastic piece on the unit. I cleaned it with a wire and shop vac and MAGIC! I was able to cancel my Sunday emergency call. Thank you!


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## moravac

*American Standard Freedom90 flashing three lights*

American Standard Freedom90 Single Stage; upflow; manufactured 2003
The furnace starts to work normally, but after 15min burners shut down and starts flashing three lights first than two lights.
There is white plastic box 4"x2"x1" close to the bottom on the right side (mine is upflow version) receiving 1/4" and 3/4" plastic tubing on the top of the box. 3/4" drain tubing is connected to the box on the side. I don't know what is the function of the box.
First I noticed water in 1/4" tubing and realized that the box is probably plugged and not allowing water to drain properly.
I removed the plastic tubing and unscrewed the box. There was some gunk in the box. I cleaned the box with plastic wire, rinsed with water and blow in the holes to make sure it is clear. I put the box back and connected the tubings.
Furnace is working fine for the last five days.


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## JohnH1

Im not sure what the question is. But if it is whats the white box it is a drain trap. It is there to prevent fumes from exiting the furnace as well as keeping air from sucking in allowing the furnace to drain properly.


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## beenthere

JohnH1 said:


> Im not sure what the question is. But if it is whats the white box it is a drain trap. It is there to prevent fumes from exiting the furnace as well as keeping air from sucking in allowing the furnace to drain properly.



The original post is from August 2005


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## JohnH1

beenthere said:


> The original post is from August 2005


_ I was trying to respond to moravac It looked as if he may have been asking a similar question to the oridginal post. O well
_


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## beenthere

JohnH1 said:


> _ I was trying to respond to moravac It looked as if he may have been asking a similar question to the oridginal post. O well
> _


I think he was just telling about his success at getting his to work again.


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## Earlcus

*Flash code Or blinking red light 3 times*

I had no ignition, but had the exhaust fan come on.
I checked out this post and it seems like you are dead on. After opening the access door. I unscrewed the access panel to the ignitor (two white wires connected it and it is were the gas pipe goes into the burner area) 5 screws, Unscrewed ignitor, (need ratchet for angle)  cleaned ignitor with 600 grit sanding paper, reinstalled don't over tighten.
Took the vacuum hose off that went in the same direction as the gas supply, blew in air and put finger over hole were air was coming out. heard gurgling noise, and then sucked in and heard a back pressure noise and felt pressure. (did all three ends this way). Reattached.
turned gas and power back on, turned up heat and it ignited.
Don't know which one of these did it and since you are in there do them all. :thumbsup:
Thanks 
Hope this helps other too!


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## rmaj

*draft pressure error- 3 flashes*

We had the same problem 3 flashes showing a pressure switch problem. We took our upper and lower panel off and found the clear drain tube was full of water and a bug which caused alot of obstruction in the clear tube. We removed the tube and cleaned and dryed it out. After ,we reconnected the tube and replace the panels back onto our furnace. So far so good it is working great. We were so greatful for your posting as we lost heat on a Sunday with a low of 18 tonight.


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## pnj618

*Same 3 flash code.*

Hey guys,
just wondering if any of you could help. I have the same (American Standard Series 90) red light flashing 3 times. I bought and replaced the pressure switch as the inducer wouldn't even come on with the old one. I have blown out the vent, and cleaned out and washed all the hoses from the pressure switch, main housing condensation trap etc. When I start the furnace, the inducer comes on, blows for about 30 seconds. Then it just shuts off, and I am still getting the 3 flash error code. I know this is an old thread, but any advice you can give would be appreciated.
Thanks.


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## jackyboy

*Same Problem same furnace...3 lights-a-flashing*

I'm wondering where the pressure switch actually is. I see the white trap with 2 clear drain tubes going into it but it doesn't appear to be an electrical "switch" of any kind. Is the switch in the trap or somewhere else? Am Standard -Freedom 90 vintage 1996 High efficiency


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## pnj618

jackyboy said:


> I'm wondering where the pressure switch actually is. I see the white trap with 2 clear drain tubes going into it but it doesn't appear to be an electrical "switch" of any kind. Is the switch in the trap or somewhere else? Am Standard -Freedom 90 vintage 1996 High efficiency


The pressure switch is located in the upper compartment. It is like a black disc with two terminals, with an orange wire coming off one and two yellow wires coming off the other. There is also a black hose coming from it to the combustion chamber. The white trap that you are refering to is the condensation trap.


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## SendEveryone

*Add Water Plugging up Furnace to the list...*

I have learned that Water can plug up an American Standard Freedom 90 Furnace or any furnace and stop it from running. The problem arises when the furnace is installed on the ground in the Basement and can get out of plumb – it settles and leans to the back or away from where the drainage tube comes out. The Furnace needs to be level or have a slight slope to the front or towards it outlet tube; otherwise the condensation water on the bottom of the furnaces pan can't get sucked out. The Furnace Fan just recycles and the light blinks 3 times.


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## bra0115

Remove both inspection covers. You will see a push switch where the top of the bottom cover rests on the furnace frame. Hold this button and see what happens. If the small fan in the top section runs and then shuts off you can bypass the sensor to rule out the ignition and gas issues. The sensor is round with two small tubes going to it. There is one wire going to the top and two wires joined together going to the bottom. You will need a test lead or a short piece of electrical wire to do this troubleshooting. Put the bottom cover on so the push switch is activated. Remove the two sets of wires from the pressure sensor. Once the small fan is running joint the two sets of wires with the test lead or electrical wire. Look in the little window at the burner box and see if it glows orange (this means your ignition is working) the gas should light and burn blue and give you heat. When the house gets to temperature remove the test lead as this only works once (the furnace will not light with the wire joined - the small fan has to run with the wires seperated before the startup sequence will work). The hoses going to the pressure switch will need to be cleaned out to get the furnace working properly but atleast you can do it in a warm house. You may also need to remove the pressure switch to look in it to see if the passageway is blocked. If there is no blockage in the hoses or passageway the switch itself may be defective. If you have a test meter, use the resistance setting and put a lead on both connectors. Blow in both sides of the pressure switch (one at a time) and see if the circuit closes (meter goes to 0). If the circuit closes the switch is good. If you don't have a meter, you can try blowing in both sides of the pressure switch as the micro switch inside could just be stuck in the open position. After letting the house heat up for a few hours and going home to get my multi meter, I tried to start the furnace up without the wires on the sensor and I saw it close on the multimeter. I put the wires back on the sensor and the furnace started up. I guess whatever was blocking the sensor cleared itself with the furnace running.


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## 64BUICKfan

*American Standard** Flash Code 3***

My furnace had the flash code 3, and after checking the vacume hose, and testing the pressure switch with a multimeter, every thing tested OK. The Flash Code 3 would still return,:confused1:. When I wiggled the orange and the yellow wires from the pressure switch at the Circuit Board the furnace would cycle itself on and the heat would work:detective:.After removing the circuit board from the furnace I discovered that the soldered connections behind the white connector were Cracked/Broken. Not only the orange wire terminal but also the red,yellow,green and blue wire terminals were cracked. Resoldered all terminals and the furnance work's like new again:thumbup:! I hope this helps :yes:.


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## hvac5646

does any body realize this thread started in 2005?


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## bob22

But the beat goes on; same furnace, different people, similar problems so its all good I guess.


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## harleyrider

64BUICKfan said:


> My furnace had the flash code 3, and after checking the vacume hose, and testing the pressure switch with a multimeter, every thing tested OK. The Flash Code 3 would still return,:confused1:. When I wiggled the orange and the yellow wires from the pressure switch at the Circuit Board the furnace would cycle itself on and the heat would work:detective:.After removing the circuit board from the furnace I discovered that the soldered connections behind the white connector were Cracked/Broken. Not only the orange wire terminal but also the red,yellow,green and blue wire terminals were cracked. Resoldered all terminals and the furnance work's like new again:thumbup:! I hope this helps :yes:.


 try starting your own thread, instead of hijacking a 7 year old thread.


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## hvac5646

:thumbsup::thumbsup::thumbsup::thumbsup::thumbsup::thumbsup::thumbsup::laughing:


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## Plumber101

harleyrider said:


> try starting your own thread, instead of hijacking a 7 year old thread.


And where's the fun in that you fun hater. LOL

I really enjoy watching all the people posting on a 7 yr post.


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## thecanuck22

hvac5646 said:


> does any body realize this thread started in 2005?


 this OLD thread helped someone in 2012 repair his furnace even though it was started in 2005, not this thread or board entirely but it certainly helped and its MUCH appreciated!!:thumbsup::thumbsup::thumbsup:


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## thecanuck22

actually the responsible thing to do would be to report my findings since i am sure more will read this as it was one of the first returns from google.

American Standard (which is basically a Trane) Freedom 90 vs.
Furnace just quit and would not turn on. Through reading the back of the panel of the bottom chamber the code was 'inducer motor' (i think). It would blink no call for heat, blink call for heat, then go to 3 flashes shortly.
Got a crash course on my furnace today.
the inducer motor is the blower motor attacthed to your vent pipe. mine would not engage, spinning the motor i was apparantly able to free it enough so that the next call for heat i sent the motor turned at least a little.
I removed it, its easy enough unplug two connections and a few mounting bolts and clips and it slides out. I found out that its like a $500 part onine which makes it about 700 retail around here...
A few tips I read were; finding a used one out there, there are some sometimes, i just missed one on ebay for 95. the tip that got me going again at least was to inject some wd40 onto the motor shaft and 'work' it in (spinng the motor).
I reinstalled it and the next call for heat it fired right up, for now at least. Maybe give me enough time to find a good used one, maybe you too.

Cheers!


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