Help with Panasonic units please

[dazdidge]

Could be a long story so please bear with me. Got called out a whil back for a problem on an older panasonic split system, phoned panasonic with fault code and they told me loss of communications between controller and indoor unit. I replaced the cable and it made no difference. While I was there someone else was at outdoor unit and accidentally earthed phase 3 of compressor contactor (don't ask). Managed to wipe out contactor and control pcb. I replaced both, but then a new fault appeared, F42. Phoned Panasonic again and they told me it was the current sensor board for the compressor, so I replaced that today, still have F42. After switching on/resetting system the indoor unit runs and the 3 way valve clicks on and off a few times then the red lights reappear on the outdoor unit (2,3,5 and 7 flashing) along with the fault code on the control pad and red light on indoor unit unit. Panasonic don'tt seem to be able to tell me exactly what is going on. The contactor is not at anytime getting a feed to the coil. Can anyone shed any light on this please? I'm starting to rip out what hair I have left.
thanks
daz

[paul_h]

Got a model number?
Does the compressor have an internal overload circuit in the control circuit?
That may be open circuit.

[dazdidge]

cheers for the reply, doesn't look like there is an internal of any sort and there are no other wires except for the crank case heater and normal power supply. If you push in and hold contactor the compressor runs no problem and draws correct current. I will go and get the model numbers out of the van if I can find where I wrote them down. It was a CU unit of some sort if that helps (probably not though)
cheers
daz

[paul_h]

Yeah CU is what most of their outdoor units start with.
Contactor coil isn't open circuit is it?
All I can say is that that fault code relates to the compressor for most units, either there's something open circuit in the line to the compressor contactor, the PCBs aren't plugged in properly, or the replacement PCBs you have are DOA.

[stefs_cruiser]

Make sure that the replacement outdoor pcb is for the correct model, ie the correct size.
the CT board gives a voltage that it compares to a reference, dependant on the size.
if for example you fited a main outdoor PCB of a smaller unit, the micro thinks you are drawing too much current.
Also check to see if it has a 5 or 8 on the end of the model number, 5 denotes single phase, 8 denotes 3 phase, obviously the currents are different.