Furnace orifice clogged

No.......

But combustion air intake IS a wide open port so spiders, mud dabbers, hornets, dirt/grime can easily get into burner area.
Even a spider web can really cause issues with air/fuel flows

Simple fix,,......clean burner assembly

I run in to that all the time- usually a flea is in the orifice. Occasionally, if the LP is contaminated with moisture, I will see a rusted manifold pipe. Depending on severity, clean (optional ospho) or replace manifold.

RVs generally use black iron pipe underneath to distribute the LP. You might want to unhook the furnace from the LP supply and use a compressor to blow out the piping from the supply end. The pipe could have been contaminated with moisture from new and has some slight rusting inside that's coming loose. I'd sure try that.

Unless something crawls in entering gas freeway using off-ramp...If that's the case...

I sprayed around water heater with bug juice, flame out keeping well away from areas that got hot.

Worked.

Old-Biscuit wrote:
No.......

But combustion air intake IS a wide open port so spiders, mud dabbers, hornets, dirt/grime can easily get into burner area.
Even a spider web can really cause issues with air/fuel flows

Simple fix,,......clean burner assembly

then fit these..

https://www.amazon.com/gp/product/B00192JFBI/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1

Thanks, y'all, for your input. Contamination in gas supply line is my top pick. One tech I talked to blamed Fracking for producing dirty fuel, but slough-off from the iron supply pipe or manifold might be to blame. If my current failure is due to clogged orifice again, I'll save the clogging material and send it to the nearest forensic lab for testing. Maybe I can use their gas chromatograph mass spectrometer like they use on Forensic Files.

Had the same problem with my 2006 Cougar. Problem was the tube that the orifice is attached to was rusting on the inside. Several months after I got my furnace fixed Suburban had a recall for that issue. Mine was a 30,000 BTU unit.