Water Flow issue - Simpson Encore 503?

I'm having issues with the water flow on this machine. The hoses seem to be fine, switching doesn't seem to make a difference. The cold tap is also fine, as when it's attached to the hot water intake and told it is hot water, the water flow is as usual.

When any tap is connected to the cold intake through any hose, the water comes through as a very, very slow trickle. Any thoughts?