My called up on a "twinning error" on a single speed Coleman Evcon.
We don't see many Coleman Evcons and I can't remember seeing
twinning error in the error code list of other brands.
The unit is not twinned. But the same company he works for replaced the board last spring. This is heating call, and the blower works when jumped, and so does the AC. Error code comes from heating only. The heating should have been tested when the board was replaced around 6 months ago, but
since he did not replace that board, we can't say the heating worked before either.