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Wednesday, February 2, 2011

Ignitor Failure On Armstrong Ultra SX 90 Furnace

Before paying a repairman to come to your home when your furnace breaks, there are a few basic things you should try. This is one of them.

Recently my region received a substantial amount of snow. Although it was all blown around, my yard certainly received more than a foot, perhaps 15 inches. The following day, my furnace, an Armstrong Ultra SX 90, did not work.
  • Furnace would turn on, hum, make noise
  • Air would come out of my vents, but it was not hot air, it was cold air
This obviously indicated a failure in the heating subsystem of the furnace. I tried a few things that did not work:
  • I cleared the snow around the air intake and exhaust ports on the outside of my home. If these are blocked, it can cause the furnace to stop working. Clearing these did not help me.
  • I cleared the snow around the natural gas meter, which as typical had a vent on it. If the vent is blocked, it can deny gas to the furnace. Clearing this did not help me.
  • I searched the internet and found a web page describing exactly my problem with exactly my furnace, but unfortunately my little tubes were not corroded or blocked, so that fix did not work for me.
  • Then, following the instructions on the inside of the furnace panel, I turned the whole thing off and turned it back on again. I watched for the fire to come on, but it did not.
A repairman came to my house. After trying to replace some of the electronics inside the machine, he finally realized that the problem was simple: the roll-out switch had tripped. The switch contains a reset button; he pressed the button, and I paid him a day's wages.

I didn't pay the man for his labor; I paid him for his knowledge. I didn't know what a roll-out switch was, but now I do! And so should you! Here is what to do:

  1. Open the door of your furnace. It lifts up, and the inside should look like this if you have the same furnace I have, an Armstrong Ultra SX 90.
  2. The roll-out switch is located at the top right of this picture, behind the curvy pipe which takes natural gas up into the silver combustion area.
  3. Reach back there and press the button on the switch. That's all there is to it.
I hope this knowledge can save a homeowner somewhere the denarius that it cost me. If it helps you, please leave a comment so I know! Before you go, a little more important knowledge:
  • The purpose of the roll-out switch is to immediately cut the gas in the event that the combustion box gets too hot. In my case, it probably got too hot because the exhaust or air-intake ports were clogged during the snowstorm in my area, but it could also indicate a furnace part which is beginning to fail. If you have to do this trick more than once, or in suspicious circumstances, then have a technician help you.


  1. Thanks! This solved my problem when the repairman thought we needed a new ignitor.

  2. Thank you! This worked for me too. Appreciate the post.

  3. MY MAN!!! You saved me more than you will ever know! May the Lord Bless you mightily!!!

  4. Thank you soooo much. This worked for me!!!

  5. Thank You so much for posting this it worked for me......Your the MAN!!!!

  6. Thank you for the great tip sir. Definitely saved me a call for a serviceman!

  7. Saved me time and money for sure, thanks Nicholas.

  8. That advice was a little bit of magic. Thanks!

  9. Perfect. Thanks for the knowledge. I had just had the repair guy out here a couple of weeks ago, and he found that the drain had clogged and caused the whole pump to be backed up/filled up with water. And then today I realized heat wasn't working again. But your post saved me a lot of time, aggravation and money. Thanks

  10. Thanks..being the wife, I looked this up. Husband went down and did as you worked.

  11. Thanks! Worked perfectly. When i first hit the switch, it didnt work, but the connecting wires looked loose and slightly corroded. I jiggled the wire and then made sure it had a solid clean connection, hit the switch again and tried it and she fired right up.

  12. Awesome read n worked for about 3 hours on the furnace then found your post n was the problem thanks

  13. What does the switch look like? I dont see a switch. :(

  14. What does the switch look like? I dont see a switch. :(

  15. Thank you!!! 9 degrees outside 45 degrees in the house. Followed your instructions and hit the reset button and heating up nicely.