Chome housing you mean?
Have you got a valve/waste gate at one end - usually a brass fitting with red painted "wheel" you turn it like a tap, all the way out is open, and flushing the system in is closed most water will divert out of the side hole - this is waste a trickle will come out the centre this is pure
The othe end should have just the side port for water in.
I'm positive that's it, I'm due to pop down the unit in an hour if not sorted I'll take a piccy or 2 hopefully that might be clearer than trying to type the answer
Darran