Came out to call for a second opinion on customers system. They had another company out to check the unit and made a repair, and the unit worked for a little bit then failed again. After checking system over I found a failed gas valve. I picked up gas valve and came back to install it. After installation of gas valve system started to fault at the control board. Control board is intermittently failing as well. Discussed with customer about repair and also replacement options. Customer wanted to replace the unit.