NT22 Suburban furnace

[Fishbone]

I took my NT22 furnace out during a major renovation and fixed the recall hose and the fiber rings on the vent tubes. I tested the furnace 3 or 4 different times before I put the cabinet in and all was working fine.I also have a CO2 alarm and it never went off. Now I have the interior done and was working in the trailer when it was about 22* outside and lit the furnace. Even using my plumbers torch, (I threw away the Chinese BBQ lighters along time ago) it was very hard to light, with a weak pilot flame. It finally stayed lit and I ran it till it was 65 inside and it shut off. I left it for awhile and when I came back the fan was blowing cold air and the pilot was out. I could not get the pilot to light with the bypass pushed, not even a hint of flame. The regulator and feed line outside were frosted over all the way down to the frame Is it possible the line has condensation in it and the small line to the pilot is frozen or is it more likely a thermocouple or dirt? I'm sure the thermocouple is not available anymore, has any one used a universal one for replacement?