Trane XB Ignition problem


  #1  
Old 01-14-13, 08:32 PM
D
Member
Thread Starter
Join Date: Jan 2013
Location: USA
Posts: 2
Received 0 Votes on 0 Posts
Trane XB Ignition problem

I have a Trane XB furnace in downdraft configuration running on propane that won't light properly.
The draft motor starts, then the hot surface ignitor glows for a while, then the gas valve energizes, but the burners don't light.
If I remove the burner box cover it will light every time. But with the cover on, it will never light. If I light it with the burner cover off, then put it on, It will stay running perfectly as long as the Thermostat calls for heat.
I verified I have 10" manifold gas pressure and have replaced the hot surface ignitor. I have a little more than 11" coming into the gas valve and have to screw the adjustment all the way in to get just a little over 10" manifold pressure. the spec for the furnace is for 10.5 ".
I have also tried disconnecting the draft air inlet hose from the burner box to eliminate there being a clog somewhere between the furnace and the roof and it was drawing air strong, but still wouldn't light with the cover on.
I also took all the gas nozzles off and cleaned them gently with a toothpick and compressed air.
On this model, the draft inlet is right above the first burner to light ( The one with the HSI ) Is it possible the draft is blowing the gas around so it isn't getting to the HSI ? Maybe a design problem that's being exaggerated by slightly low manifold pressure ?
I'm starting to run out of ideas. Any suggestions would be welcome.
 
  #2  
Old 01-16-13, 09:07 PM
D
Member
Thread Starter
Join Date: Jan 2013
Location: USA
Posts: 2
Received 0 Votes on 0 Posts
To follow up, I took a piece of tin foil and made a shield of sorts over that burner to deflect the air from the draft and it ignited fine with the burner cover on.
Rather than adhere a permanent cover, I tried moving the ignitor a little bit closer to the burner orifices ( without being directly in the flame when lit ) and that solved the problem as well.
So, I would have to conclude there is a design problem with the the location of the draft outlet and the workaround is to bend the ignitor mounting plate to position the ignitor as close to the burner flame as possible without remaining in the flame when lit.
 
 

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