I purchased my own heat pump and air handler online and had a local contractor install it. When brazing the lineset end near the air handler, the installer doing the brazing didn't have any wet rags or spray around the inside or outside of the unit. The foreman stopped him from brazing (he had already brazed the elbow-so 1300 F was applied to tube) and had him spray it down, It sizzled pretty good and for quite awhile. I could see the look off concern on the foremans face, no mistaking that. I don't know if they pulled the sensing bulb away or not because I didn't get a chance to look inside before the job was finished and covers put back on.
After they left I looked inside and discovered a big gash in the cooling fins on the A-Coil. See attached pics. They did have the coil out and had removed the horizontal drip pan. Someone did the deed and stuck the A-coil back in hoping I wouldn't notice I guess.
Anyone care to comment about all of this and assess my pics and severity of the damage to fins and possibly to TXV valve? Can you ascertain anything from the heat marks on the tube?
PS. Yes they did use nitrogen and evacuated the lines before filling with Puron.