TL:DR - Incorrect/Misleading diagnosis. Suggested ...

TL:DR - Incorrect/Misleading diagnosis. Suggested we buy a new furnace by red flagging our furnace. Our furnace is 100% normal.
We had Pyramid come give us a diagnosis on our furnace after a carbon monoxide alarm went off 1 time. The service tech wore a mask and was pleasant to deal with. The tech determined the furnace was bad by highlighting the color of the flame being orange and not blue. This was the only test he performed which should have been a red flag but I didn't know any better.
After getting a second opinion from a company who is a preferred supplier of the furnace manufacturer, they confirmed there is nothing wrong with our furnace/heat exchanger. This tech used a carbon monoxide tester in the air flow and used a mirror/scope to determine the health of the furnace/exchange. The flame also stayed blue and he showed me how 'some' service techs trick people into thinking their furnace is bad by blowing into the flame causing it to be orange. I'm so incredibly happy I got a second opinion as that cost me a service charge instead of a new furnace.
I really hope this tactic was not used on purpose to try and get us to buy a new furnace of a competing model manufacturer. Pyramid quoted us for a new furnace and failed to mentioned just the heat exchanger could be replaced. I understand the part would be very expensive for Pyramid to replace as they are not a Trane dealer but they could have at least given me that option.
I called 2 other companies and they both suggested that pyramids initial diagnosis didn't seem right and advised I get a second opinion. One even mentioned that Pyramid was a good company so perhaps I just got a bad tech.

Judging by the other reviews, the company is great so maybe this was just a fluke. I guess the lesson is always get a second opinion.