I use mine with a small (1psi) pressure on the corny. The beer pick up from the engine is just clamped onto a beer out disconnect.
This is a bit of a pain at the moment as the gas pipe only just reaches the corny I'm currently drinking when the garage door's open. To get around this I've bought another gas management board from Norman and will be picking up another gas cylinder to connect it up more permanently sometime soon.
If I think I'm on for a bit of a session I transfer a few pints from a corny into one of my 11l cornys and just leave the pressure release valve open while I dispense. Obviously this is only worth doing if I'm confident of drinking the entire contents in a day or two. Which I usually am
Works beautifully
/Phil.