I have the CP31 W/D as well.
I feed it and the main unit off a dedicated circuit breaker from the panel so as to not overload other circuits in the darkroom.
I use a GFCI repeptacle and put a bit of blue tack over the little green 'protection working' LED in it so as to not fog prints.
The thing takes it's signal from the main unit, via a non-standard din style plug. I think it has 3 pins.
It takes signals from the input sensors on the main unit to tell it when to fire up the i/r heater.
Mine started acting wierd a year ago, overheating. I replaced all the electrolyitic capacitors in the w/d board (watch out, one is bipolar), and it is back to behaving itself.
I never have figured out what the switch on it's board does; mine dries the print well in either position.
I have previously swapped capacitors in the main baord, and installed a new battery (I used a surplus handsfree phone rechargable battery).
The digital thermostat still did not work after this. That is when I fed the tank 1 a signal derived from an analog thermocouple reading off of the port where replenisher for tank 1 fed in. I stll have (somewhere) the notebooks (messy sketches) of the wiring if it helps.
I also have the operations manual from the old Jobo USA web site before it's demise.
There are good exploded view diagrams too I think I recall.
I can scan them and mail you a CD for the cost of a few bucks if you feel it will help you.
I fixed mine before finding this documentaion, so they are not really a must, but would be useful if trying to source an OEM part by part number.
The input sensors din plug is a wierd pin configuration as well. Mine has contact fingers broken in the main body female part so that only one sensor eye fires the unit out of standby. The print dryer still seems to work ok off of one yee, but the reprlesiher duty cycle signal would be screwed up if I used that option.