trane xe 80 help

Reply

  #1  
Old 11-09-08, 04:53 PM
Member
Thread Starter
Join Date: Nov 2008
Location: central US
Posts: 10
Received 0 Votes on 0 Posts
trane xe 80 help

Ok here we go,
My Trane is derailing and Iím not sure what is going on. It starts out when the t-stat calls for heat, it will light normally. It will run fine for awhile, about 5-10 minutes, then the fire and the circulating fan will stop and the exhaust fan will continue to run. Mind you the temp in the house is still not at the required level. After a few minutes, the unit will attempt to relight the fire. It will go thru the normal 3 attempt cycles and then blow cold air. While the unit is attempting to fire everything in the start up sequence seems to be fine except no gas and of course no fire. The gas valve is getting the required 26 volts while the glow plug is energized, but still no fire. I can leave the unit off for a while, and then turn it back on and it will fire normally and the cycle starts over.

Now the heater guy came out and said to have the gas pressure checked by the gas company. He said that the water heater was taking the pressure from the furnace while the water heater was running. I find this hard to believe, so I tested the theory. I had both appliances running at the same time and all was good until the furnace tried to relight and the situation was the same.

What will a bad high limit switch do? Or what will a bad or weak compartment temp sensor do? I hope itís not a bad gas valve, those things are expensive. I'd hate to change it and it not fix anything. Can the gas valve be adjusted? How? What equipment will I need?

Thank You for any help you can give.
 
Sponsored Links
  #2  
Old 11-10-08, 06:19 AM
Jay11J's Avatar
Member
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 18,427
Received 0 Votes on 0 Posts
Originally Posted by tagius View Post
The gas valve is getting the required 26 volts while the glow plug is energized, but still no fire.
Have you heard a click of the valve in the past, and when this happens, do you hear a click of the gas valve?

I can leave the unit off for a while, and then turn it back on and it will fire normally and the cycle starts over.
Not knowing the full model # and age of the furnace, do you have a fault code on the control board?


Now the heater guy came out and said to have the gas pressure checked by the gas company.
He didn't put anything on to check the gas pressure?


He said that the water heater was taking the pressure from the furnace while the water heater was running.
What size is the gas line going to the water heater and furnace? Is the main gas line the same as the two?


It could be that you may have a bad pressure regulator on the meter outside.
 
  #3  
Old 11-10-08, 03:28 PM
Member
Thread Starter
Join Date: Nov 2008
Location: central US
Posts: 10
Received 0 Votes on 0 Posts
Have you heard a click of the valve in the past, and when this happens, do you hear a click of the gas valve? The valve always clicks during all start-up attempts.
Not knowing the full model # and age of the furnace, do you have a fault code on the control board? Model #1UD080C936BO When the unit fails, the fault light flashes twice, pause, flashes twice, pause... Control board code, "system lockout-check line polarity". Just for S and Gs I swapped the input wires and the same thing happens.
He didn't put anything on to check the gas pressure? I don't think so, I wasn’t here, my son was when the heater guy came by.
What size is the gas line going to the water heater and furnace? Is the main gas line the same as the two? The gas lines to both appliances are the same size. Yes I believe the main is the same size or slightly bigger.
The unit worked fine all night last night, but the same thing in the morning. Why would the fire and the blower shut down in the middle of the heating cycle? The house is still calling for heat. Is the furnace getting too hot? Is the thermo sensor weak causing the shut down? Or is that what it's supposed to do?
 
  #4  
Old 11-10-08, 04:30 PM
Banned. Rule And/Or Policy Violation
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
Received 0 Votes on 0 Posts
Originally Posted by tagius View Post
Why would the fire and the blower shut down in the middle of the heating cycle? The house is still calling for heat.
Is the exhaust fan still running?, or does that also shut off with the flame? If it does, I would want verification that the thermsotat wires are still calling for heat. You can check and see if the W terminal in the furnace, where the skinny 24 volt wires screw on, and have abbreviation letters like R, W, Y. G, etc., has 24 volts to ground.
 
  #5  
Old 11-10-08, 04:39 PM
Banned. Rule And/Or Policy Violation
Join Date: May 2007
Location: Wisconsin
Posts: 8,629
Received 0 Votes on 0 Posts
Originally Posted by tagius View Post
Why would the fire and the blower shut down in the middle of the heating cycle? The house is still calling for heat.
Does the blower fan shut down at the same time the flame goes out?
 
  #6  
Old 11-10-08, 04:41 PM
Member
Thread Starter
Join Date: Nov 2008
Location: central US
Posts: 10
Received 0 Votes on 0 Posts
Yes, the exhaust fan stays running when the fire shuts down.
 
  #7  
Old 11-10-08, 04:45 PM
Member
Thread Starter
Join Date: Nov 2008
Location: central US
Posts: 10
Received 0 Votes on 0 Posts
Yes the circulating fan shuts down when the fire shuts down.

If the heater is able to warm up the house to the point where it no longer calls for heat, the unit will work fine. Now this is why I think there may be a bad thermo sensor. If the unit is allowed cool off between starts, it works fine. Am I way off base or am I on the right track?
 
  #8  
Old 11-21-08, 08:07 PM
Member
Thread Starter
Join Date: Nov 2008
Location: central US
Posts: 10
Received 0 Votes on 0 Posts
So there's more, the darn thing starts working fine, for a while. Then, sure nuf starts doing the same thing. But there's more. I sit and watch it do it's thing. I turn it on and give it the call for heat and she fires right up. It goes along for awhile then the fire just goes out, but there is still a call for heat. She immediately tries to start back up and no good. So I turn it off and let it cool, once cooled down I turn it back on and wham. She fires right up, I let it run and for no reason the fire goes out. then the cycle continues.

I jumpered the resister high limit switch and the fusible link and more of the same. I think it is either a bad gas valve or the controller board. I'm leaning to the gas valve. I called the heater guy and sure nuf it works good. No problems. Works fine for a few days and then starts over again. I called the guy back and he changes the gas valve and all is good. So far.

We can consider this one closed for now. Now i didn't get much help from the so called experts here and I taught myself all about the furnance. So I think I will no longer need the heater guy.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: