When you switch the power on the compressor switches on for 30secs then off 60secs and the middle one of five lights flashes at the same time, continues to do this until you turn the power off.
Any ideas ??
Customer is old aged and ill, would like to get this one correct first time.
by the way I meant to say that the power to the compressor is being switched off and on by the control PCB which has connections that are similar to a standard T/Stat setup.
Just for the record this turned out to be the Control PCB, which was clicking and switching the compressor off and on in a 30sec cycle.
The sensor was not the fault as I tried it first.
PCB Part No 493483 @ £59.55 inc vat & postage (thanks to Chris)