Code 49 means the control board is getting a bad reading on the cold water inlet circuit. Can be a faulty valve, faulty wiring or the control board itself is getting the correct reading but thinks it is wrong. Seeing as you have replaced the valve twice, you can rule that out. I think you will find it will only be fixed by replacing the main control board. Maybe the original faulty valve damaged the board. It has happened before.
Lincoln Appliance NZ
September 2018