Hi,
I have an Armstrong ultra III 80 gas furnace that is blowing cold air. If I reset the furnace, I get heat but after the initial reset, I get cold air as oppose to heat. I have replaced with a new filter, area is unobstructed. I checked online and someone with a similar problem has indicated it may be the rollout limit switch. Note, I am clueless about HVAC or appliances so I called in an HVAC technician and paid him $80 for 15 minutes which he said there's nothing wrong. I was unhappy because he made me feel dumb. This has happened again and he told me that I just need to flip the reset switch. I don't think I should be resetting the furnace every few hours. I felt ripped off and before I call another technician, hopefully, I can get some advise.

Thanks,
Alex