Burner cycles on Furnace

[GJRVers]

Hello everyone. My furnace is having issues. When stat is in heating the blower comes on as normal, followed by the burner. That is where the problems start. Sometimes the burner will stop in a matter of 1-3 seconds and other times it will go 10-20 seconds. please note the blower stay running. It does this for 10 minutes or so then will stay running until temp is met and cycles off like normal---burner then blower. I have checked the sail switch twice and it was clean both times. I cant find any info on operations in higher Altitudes for this furnace. I did notice i had more issues when I was at 4500 feet or higher---maybe just a coincidence. We were at 8200 feet in Yellowstone with no issues with the generator of HW heater. It will act up at sea level but seems to "catch" after only one or two cycles. Any suggestions before I make the dreaded warranty call and they have my rig for 6 months??

[RogerR]

You might have a dirty pilot light tube, failing flame sensor or the flame sensor may be right at the edge of the flame and need to be re-positioned. If you haven't done it yet, go out side and make sure no wasp nests, etc. in the intake/exhaust port. Look inside with a flashlight but watch out if they are home!

[GJRVers]

Thanks Rodger--no wasps, I had it open last week--- but thanks for the thoughts on the flame sensor-. Let me pull the manual to find its location.

[Rustynuts]

If the furnace blower starts and the burner doesn’t even try and light it’s usually the sail switch but if the blower starts and then the burner try’s to ignite and only burns for a short time period and shuts down like yours, 9 times out of 10 it’s the high temp sensor. When he sensor ones bad it tells the board that it is to hot and shuts down. Easy to replace, just 2 screws.