# Trane XE80 - cold air!



## chances04 (Feb 2, 2007)

*Additional info*

It isn't the thermostat; I have replaced that and it is still blowing cold air. 

Thank you again for reading this.


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## #CARRIERMAN (Oct 18, 2006)

Hi chances04

There are several things that cause the symptoms you described. The most common is an ignition lockout. This could be due a dirty flame sensor or flame rectification circuit not reading ground. Shut the power off to the furnace, locate the stainless steel rod and remove it. Use steel wool or a wire brush and clean. Reinstall the flame sensor and fire up the furnace. If this does not work it could be a limit switch tripping or the pressure switch is sticking either closed or open. I am taking a educated guess that the flame sensor is the problem. If you could give a little more detail as to what it is doing, I can give you a more accurate solution. Check the system filter, if it showes dirt replace it.

Good luck
Rusty


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## chances04 (Feb 2, 2007)

*RE: re:*

Thank you, Carrierman. I've been trying to isolate, so I am just replying to your suggestions.

Now, The unit is blinking a '2' code, which evidentally is a 'System Lockout, check line polarity' alert'. 

Is this something I can repair myself, or should I have the pro return to repair?

Thanks again for your assistance, Carrierman.


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## #CARRIERMAN (Oct 18, 2006)

Hi chances04

If you are comfortable with wiring this is no problem to correct. Or if it is on a two prong plug all you have to do is flip the plug over and plug it back in the other way. If its on a three prong plug, locate where the wires go into the furnace from the recepticle after you have unplugged the furnace. Switch the position of the black and white wires. See if this corrects the problem, if it does you will need to make a permanent change at the recepticle its self. You don't want to leave furnace permanently like this. It won't hurt the furnace, but it may be against code in your area. Just use this for testing purposes only, make the permanent repair at the recepticle.

Good luck
Rusty


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## rakes9720 (Dec 13, 2006)

Since it only happens periodically, it might be a loose ground connection.


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## eoyads (Feb 21, 2008)

*I had the same problem*

I had the same exact problem and had a technician come out and all he did was tap the gas valve during the start up and it started up just like that. According to the tech the valve was sticking and not opening when called for heat and by tapping it loosen it and it opened. You might give this a try and see if it works. You can hear the valve click during the start up. After three times and the valve doesn't open the system stops trying to light and just blows air hench the cold air and colder mornings.


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## Thome (Oct 12, 2009)

I have the same furnace and have found like most make of furnaces of this vintage, the fire sensor needs to be cleaned once a year to prevent the cold air problem. The need to clean the fire sensor is by far the most common cure to this problem.


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## eoyads (Feb 21, 2008)

*Same problem and fix it*

If you are comfortable with sodering, all you have to do is locate the gas valve and remove the black thing on top where all the wire are attached to. Once removed flip it over and you will see a green chip plate with contact points (looks like tiny silver volcanos) for the wires. Find the one that is not completely connected and resoder. I used a voltameter to help me find the exact spot. Once I did this it worked ever since.


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## Thome (Oct 12, 2009)

*Trane XE80 - cold air with lockout*

I find this thread interesting, especially since I have a similar problem and same model furnace. I have a furnace blowing cold air. I have to drop all power from the system for a while before the furnace will reset and allow for troubleshooting. Once reset here is what I find. 
1. The draft blower starts while getting a normal call for fire
2. Igniter gets hot
3. Igniter goes out before gas turns on.
The sequence continues until the control board locks out. Once locked out the furnace blower runs continuously. I checked the heat sensors and all ohm out good (closed). The draft blower switch seems to be working. I can fine voltage to the switch that passes once the draft blower starts. Anyone have any suggestions? 
​


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## diyorpay (Sep 21, 2010)

Clean flame sensor/thermocouple.

http://www.youtube.com/watch?v=I86joWL66aE&feature=related


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## Thome (Oct 12, 2009)

Thanks for link. I am aware of the problems with a dirty flame sensor, unfortunately the problem I have is that I do not get the flame at all... any thoughts?


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## irfan_siddiqi (Feb 21, 2011)

*Trane XE80 Problem - Loose wires?*

I have a similar problem with me XE80: it blows cold air when responding to a heat call every once in a while. During one of these cycles when it was blowing cold air, I opened the panel and just wiggled the wires on the thermostat input on the controller board and the unit immediately responded to the heat call. The LED was flashing a normal code before I moved the wires and give the code for a heat call when after wiggling. Looking at the past thread, I would surmise this is not a problem with the flame sensor, etc... but I am unable to find any loose wires also. Someone mentioned a loose ground...how is the board grounded? Any other suggestions? I also notice that when it goes into this mode, then the red terminal only outputs 7 volts instead of ~ 27 V.


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## MnEng (Nov 10, 2011)

*Fyi*

I have a Trane XE80. It has worked flawlessly for the 2 years I have lived in my home, only problem was once when I installed a 3m filter that was the blue level electrostatic and the pressure drop thru the filter was so great it choked the furnace causing a high limit failure. I switched to the purple and it was fine again. Then a few nights ago it just started blowing only cold air and showing 4 blinking lights, high limit error. I had just put in a new filter, I checked all limit switches with meter, removed filter temporarily to eliminate as a problem, checked A coil for dirt or blockage, checked board and all electrical connections, yet just old air. So I decided what the heck I'll clean the flame sensor since its so easy... Bam the thing fired up. I don't understand why the flame sensor would be associated with a high limit error, but my suggestion would be if your furnace has these symptoms, try the flame sensor.


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## how (Feb 26, 2011)

Hey Thorm
Cheapest repair to try would be an igniter change. Lots of hot igniters have the wrong amp reading for the board to go to the next stage.

The more expensive repair is a gas valve replacement. (Check first that it's "on" , or that you have gas, or that the relevent electrical connections to the gas valve are good.)

What does the led say?


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## how (Feb 26, 2011)

Hey chances04
As rakes9720 suggested.
If your furnace locked out and sometimes has an led fault code and sometimes doesn't, then I would be looking for a poor ground connection anywhere from inside the furnace to the electrical panel. Look for slightly loose screws attached to green wires. Loose grounds in junction boxes, on/off switch box or even lumex cable connections when the ground is the external electrical sheathing.


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