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-   -   american standard freedom 90 just blows cold air (http://www.diychatroom.com/f17/american-standard-freedom-90-just-blows-cold-air-157952/)

lamarch77 09-25-2012 01:57 PM

american standard freedom 90 just blows cold air
 
I have an American Standard Freedom 90 that has been working intermittently lately The furnace, has a flashing LED diagnostic indicator which flashes 4 quick flashes–which according to the manual means “thermal protection device open. I have tried to shut everything down and wait 5 minute then turn everything back on and turn the temp up.....just endless cold air........please help, I dont have the money for a service call

techpappy 09-25-2012 04:11 PM

not that familiar with latest equipment but, look for a reset button near burners and reset OR just turn power off and back on then see what happens.."thermal" switch open seems like might be due to lack of air flow causing heat exchanger to overheat....could be dirty filters, "A" coil, furnace fan etc., OR defective control or thermal switch..thermal sensor looks like silver? button on front of unit with two wires going to it....

Check filters, A Coil to make sure they are clean and clean if neccessary before anything else

techpappy 09-25-2012 04:24 PM

may also be induced air fan OR ventor motor or air flow sensing lines ..if so equipped...induced draft motor should run as soon as stat calls for heat..this creates air flow for exhaust..the air flow must be proven by the air flow switch..( looks like small diaphragm with wires and tubes going to it..Disconnect tubes and blow/suck on each one ..should hear switch clicking on and off...Once air flow is proven the ignition glow coil OR spark igniter should come on and light the gas pilot..Once the gas pilot is proven then the main gas valve will be energized and open main gas to burner,,then, once the heat exchanger warms up the circulating fan then, comes on to circulate warm air

danpik 09-25-2012 05:44 PM

If the blower fan is running whenever the power is on to the furnace then I would suspect a bad High Limit Switch.

This may be the type in your furnace...

http://img.photobucket.com/albums/v6...mit_switch.jpg

What you would see is the black side with the two wire terminals on it. This is one of several "thermal protection devices" on the furnace. When this type goes bad the fan usually comes on and stays on.

There may also be one or more Rollout Switches around or near the burners. These devices are sometimes resetable depending on the type.

This style...

http://img.photobucket.com/albums/v6...chbackside.jpg

shown from the back side has a small push button in the center to reset it. The front side looks like a small 1/2" button.

beenthere 09-25-2012 05:53 PM

Check your air filter. It may be dirty and causing the furnace to go out on high limit or aux limit.

techpappy 09-25-2012 07:02 PM

Right ON! Now I know more important information. Good Stuff!!

lamarch77 09-26-2012 08:42 AM

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Ok I opened up the freedom 90 to try and find the filter ( just bought the house a few months back) could not find it any where. I m I just blind? heres what it looks like.

lamarch77 09-26-2012 08:47 AM

moving on
 
2 Attachment(s)
ok so I cant find the filter like I said so I thought I'll look for things that you all showed me ...this is what I found ( I found the circle with two yellow wires coming from it with a reset switch in the middle, I could not get it to push it and stay in) Then I came to the wire thing by the burners which looks bad I tried to clean with steel wool......the tip just broke off :whistling2:

lamarch77 09-26-2012 08:55 AM

3 Attachment(s)
ok now I think I may need those two part replaced right ? be for the heck of it just in case thats no it I'll post closes ups of the in side of the cold hearted beast. I would also like to say thank you to all who replyed and shared the knowledge:thumbup:

techpappy 09-26-2012 08:56 AM

That flame sensor is called a flame rod and should definitely be replaced.

The filter is in the back of the unit where the circulating fan motor is. Sometimes accessed at side of unit as well. You will likely have to remove the access door at the back to get to the filter..OR there may be a slot in the side of the furnace where you can access the filter to pull it out.

lamarch77 09-26-2012 09:20 AM

there is no way to get to the back it is in a little closet that picture shows the whole room.

techpappy 09-26-2012 09:56 AM

Then it is installed wrong. You need access to change filter, service/replace circulating fan, check for cracked heat exchanger etc.

OR

Is there possibly an access from top or bottom of the unit. Maybe in basement/crawlspace.

lamarch77 09-26-2012 09:58 AM

a crawl space

lamarch77 09-26-2012 09:59 AM

i never thought that there would be parts of it down there, thank you

danpik 09-26-2012 10:47 AM

Quote:

Originally Posted by lamarch77 (Post 1017670)
ok so I cant find the filter like I said so I thought I'll look for things that you all showed me ...this is what I found ( I found the circle with two yellow wires coming from it with a reset switch in the middle, I could not get it to push it and stay in) Then I came to the wire thing by the burners which looks bad I tried to clean with steel wool......the tip just broke off :whistling2:

Ok, the rollout switch can be tested with a continuity meter. The little button on the back looks to be in the normal position. Push in on the front of it. If you hear it "snap" then you just tripped it. Pushing the putton on the back will then reset it.

The flame sensor as mentioned needs to be replaced. How that furnace stayed lit with a rod like that is beyond me. They need to be as clean or cleaner than the part near the ceramic to work properly.

As far as the filter...Wherever the cold air return duct comes back to the furnace is is where the filter "should" be located. If it is not there then follow the return back along the length and see if there is a location where one may slide in. Also look in the cold air return vents and see if they put one there. I have seen it in the past.


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