Active job

Diagnose problem with heatpump

I had a Fujutsu AST9LSACW installed about 7 years ago. Recently it blew a fuse when I turned it on. When restarted the LED operation light flashed and the unit wouldn't operate. I managed to get hold of a self-diagnosis table which suggests the problem is a "Serial Signal Error" and that the "Normal Serial Reverse Signal can not be received more than 10 seconds". I've been told by someone at Fujitsu this means there is likely to be a problem with the board in the outdoor unit and it's possible a short in something like the fan or compressor has caused it. I need someone to come and test the unit to try and isolate the problem.