Verifying a cracked heat exchanger
The tech said he checked by feel and with a mirror, and around the dimples ("left front edge") he found two areas of concern. One he could feel had a slight edge like if you had a piece of paper laying on a tabletop, and you ran your finger over it. He said it was small, less than 3/4". Then he took a mirror and put it behind the crack so he could look at it. The other one he said he could see but not feel yet.
He said the unit was appropriately sized for the house. They did not install it. We are terrible at changing the filter, and he didn't come right out and say that was the cause, maybe because I asked him not to lecture about changing the filter when he arrived. But I'm thinking that is likely the cause....
Who would I call to get an unbiased second opinion? If I call another HVAC company, they may say the same thing hoping to get the new install job too?
Thanks for your help.