Ok, the full instructions can be found here ->
SF-800 Temp Controller Instructions
After it did not work, I took all wiring apart and did it step by step to make sure everything was right.
I hooked up the power without the sensor so as to get the error code LL, meaning the sensor is open circuited.
So, we have power and the unit recognises there is no sensor attached and displays the code, LL.
Next I attached the Sensor.
With the unit powered up, it displays the temperature. At this time, the timer is going and the OUT light is flashing. The timer is for compressor delay so its not switching on/off all the time.
So we have power and a temp reading and the timer is working, after two minutes, the relay clicks and the OUT light stays on.
Next I connected the power to the fridge (I'm using lamp for testing but it does the same with a fridge)
Tested, nothing happens after the relay switches.
I replaced the power outlet wires with my multi-meter and reset the unit.
Beware, even bigger photo! - Wiring and Fluke -
Before Relay Clicks
So it reads 0.65-0.7VAC while the timer is counting down.
Once the timer finishes and the relay clicks, it goes to...
Beware, even bigger photo! - Wiring and Fluke -
After Relay Click
Its gotta be the unit yeah? Or, perhaps I'm a complete numbskull and did something wrong! Can anyone see a problem with what I've done?