Hey,I have a bard hvac unit model #Wa373-a15 co-worker installed unit he told me that he saw smoke coming from transformer.I investigated found that there was no low voltage coming out of transformer to terminal board.found t-stat wired incorrectly I'm pretty sure this caused the transformer to burn up can anyone confirm or give me any feedback thanks in advance

It definitely can cause it. Put a 3 Amp automotive fuse on the secondary.

Maybe you can get the magic smoke back in <G>