I don't have a copy of the owner's manual to properly troubleshoot the furnace. So, I just follow the written instruction on the cabinet. I turned off the switch and the gas valve, and then waited for the smell of gas. When I didn't smell any gas I then proceeded by turning on the gas and the switch. The blower started running and the igniter started glowing red, but the burner did not lit. I repeated this procedure the second day with same result, the burner won't lit. Appreciate any help.

If the ignitor glows, that bypasses a lot of troubleshooting right there. Either the gas control or something in the gas control circuit is the problem. I think I smell an ignition module, but I could be wrong from way over here.:rolleyes:

How many pressure switches does your furnace have? If two or more, then the one lets glow plug come on, and the second or third let the gas valve open. Can you post a pic of the inside of your furnace.

Ignition is working on your furnace, now we need to find out what is stopping gas vavle from opening. May be a bad pressure switch, gas valve, relay, control board, plugged drain lines, so on, so on. Please give some more info , and we will do our best to help.

Does the XB80 have more than one pressure switch?:confused:

I'm not real familiar with tranes, but if it is a 90+ furnace, they usually have more than one pressure switch(newer models, within the last ten or so years, give or take) Just hoping they will post a pic of their furnace.

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Attached pictures were taken before and after I did a test run again of the furnace. This time the burner lit as indicated by blue flames. But only for a minute or two and then it went out again. At least I know that the igniter and the gas valve work. I have no idea on what to do next. Correct me if I'm wrong, but it looks like there's only one pressure switch for this model.

From the picture it looks like the plastic tube from the pressure switch to the unit is complete flat? If so that could be a problem. Try to put a temporary jumper across the pressure switch wires.

Yes, your furnace only has one press switch. I just wanted to know for sure. The pic does make the plastic tube from press switch look flat, but I'm guessing it is just an optical illusion. Either way, try hvacs advice first and let us know if the burners will stay lit.

PS,

Great detailed pics. Furnace looks very clean.

I believe that I am having the same problem as described here. My XB80 has a single pressure switch also (similar to pictures here). As described, the burner comes on for several seconds after the igniter lights up. Then the gas turns off. It will cycle like this a couple of times, and then just stop lighting up. If I power it down for several minutes, I can repeat the whole process. Does this point to the pressure switch needing to be replaced?

Trane Model XB80 / TUE100A948

Any insight would be greatly appreciated --- Thanks.

One additional piece of information. I shorted the pressure switch (i.e. bypassed it with a wire), which resulted in the igniter never coming on. Is this what is supposed to happen?. If so, can I assume that the pressure switch is still good? Then I need to look for another cause. --- Thanks.

It's the flame sensor

One additional piece of information. I shorted the pressure switch (i.e., bypassed it with a wire), which resulted in the igniter never coming on. Is this what is supposed to happen?....If so, can I assume that the pressure switch is still good? Then I need to look for another cause. --- Thanks.If you jumped/shorted the switch prior to starting the cycle, the furnace would recognize this as a stuck pressure switch & not allow a heating cycle. The switch circuit must be recognized AFTER the inducer starts.

I am having the same problem. I can power it down then power it back on and this works for a short time. Also try tapping on the pressure switch.

Could this be the ignighter?

The switch has to be open before start up then close after fan starts.

You have to leave switch open until fan starts, then close switch simulating pressure.

My furnace fan regoler on I set the tem. But fan not off

My friend is having the same problem

Sorry if you have already received this already. But I am experiencing the same furnace problems as you had in 2009. What did you do to get it fixed? Please contact me [email protected] thanks Michael

(Ahem)

I know this is an old thread but I ran across it while trying to find out what my own unit (just like this) is doing.

I actually found this begfore I checked the codes but my blower has been running but the burner not working (actually working again after shutting the unit off for several hours).

As it turns out, I also have the same error code 4, which is listed as "Open Limit Device"


If you will refer to the screenshot of the manual I have circled in orange the circuit I believe to be applicable and there are sevral switches "daisy-chained" togetther so that if any one of them is open (I'm assuming "open" it could be "closed") the burner will go out or fail to ignite as the case may be.

I've also marked the switches and you will see that there are two thermal cut outs, a pressure switch, and 2 flame rollout switches in that circuit.


Also I have copied the photo showing the pressure switch with the colapsed hose attached and circled those items in orange.


It appears to me that the unit in question has a colapsed hose to the pressure switch and I believe the reason for this is that unit has a stopped up return air filter, causing excessive vacuum to that hose/switch combination, and also believe that this condition will either:

A) cause to high a vaccuum to the pressure switch (it must sense vacuum or "negative pressure") causing the pressure switch to go open

OR

B) the low airflow condition is causing the firebox to overheat and thus is tripping one or both of the thermal limiters (thermal cut out switches)



In either case, this unit needs to have a new filter (or if you're like me you need to wash out your permanent filter) AND possibly install a new hose, as this one may not regain it's shape.

My own filter needed to be cleaned and after cleaning it I had MUCH increased airflow, and although I have only run my unit an hour or so since cleaning the filter, it appears to be operating as normale.

Here are links to some manuals and there is some overlapping/duplicate information in them, the screenshot is from the first one but again, there appears to be the same info in most of them and some have other info as wewll:



http://www.bayareaservice.com/wp-content/uploads/2011/12/XB80-Service-Facts.pdf

http://www.aireng.com/clientuploads/Trane_Data_Guides/Furnace/tud_r9v.pdf

http://www.aireng.com/clientuploads/Trane_Data_Guides/Furnace/tud_r9v.pdf

18 CD24D1 5[1] Trane XV80 Installation Guide pdf free ebook download from www.munchsupply.com (http://ebookbrowse.com/18-cd24d1-5-1-trane-xv80-installation-guide-pdf-d366683508)

http://www.hvacprotech.org/toc/FileShareEarly/TUD_GasFurnaceOperation.pdf

Document Details | XB80 TRANE USER MANUAL (http://acrepairshop.com/doc_details/32-xb80-trane-user-manual.html#.UOSwjKzVprr)

XB80 - Gas Furnace | TRANE (http://www.trane.com/residential/products/gas-furnaces/xb80-gas-furnaces)

When you jumper pressure switch, you need to wait until the inducer motor starts and reaches full speed and then put your jumper across it. Then your ignitor will glow, then burners should light. If ignitor glows and burners do not light, you may have faulty gas valve or bad control which is not sending 27volts to the valve. Pull wires from gas valve and start the whole cycle over with a volt meter across both wires set on ac volts, then wait for ignitor to glow, at this time there should be 27 volts read on meter. Be patient while waiting for 27v it takes several sec. If voltage is noted, then you more than likely have a faulty valve, make sure to re connwct wires and cycle again. If no voltage to valve, then control board is culprit, check 12 pin connector for secure connection. Hope this helps