I have a Porter Cable 150 psi. How do I go about blowing the lines? I usually have my landscaper do it. He connects the compressor to the outside water faucet once I turn off the water line from inside. I would need the connector used to attach to the outside water facuet so I could connect the compressor to it correct? How do I open each zone? Is the black screw on each valve turned to open each zone line? Thanks