Thanks to another thread managed to get into the factory setting but...

There are two small water chillers, two compressors each didn't get any model numbers as were subbing to the guy who got those details whilst I was with him. Carel controller with three buttons down each side, modem type plug connects to the PCB inside. Alarm, Prg, on/off on the left. Up, enter, down on the right.
The front controllers were replaced on both units as the buttons weren't always working. Not sure what went on there but it seems one chiller all good to go no real drama.
The other came up error 31, probe B2 not connected / open circuit.
No B2 probe on both chillers. Needed the factory password to configure the probes. Got to the screen to dis/enable probes, selected B2 and changed Y to N. Each time the N changed itself back to Y as if it wouldn't let me change it. The other probes you could change.
Ended up plugging a random probe in to get it operational (I think it was an ambient sensor but not sure where I saw that now). It read 48*C but ran, no errors still couldn't program it out.

Anyone make any sense of that and can explain why it wont program out?

Cheers,
Andy.