Note: you should not follow my advice. This is how a computer programmer winterizes a system and is clearly what not to do!
- attach a compressor without understanding how your pressure regulator works (mine is loosen = less pressure ?!?!?) if you're asking what's a pressure regulator just stop now
- open the city water valve with your compressor attached!
- assemble cast iron fittings without lots of teflon tape
- walk back and forth to the timer control
- expect things to go as planned
I assembled my "adapter" and when connecting it to the system the pressure instantly shot up to 80psi - the danger zone for PVC. You don't want to be above 60psi - city water pressure. Anyway, I figured lets see what happens to that zone I don't use that much...it turned on and worked like normal. The big zone never did lift the sprinklers, so I'm a little worried it didn't get blown out enough. Hopefully we'll be okay here - south of the mason/dixon.
My valves have little manual override tabs that I discovered after walking back and forth a bunch of times to the control in the garage. Next time I'd use them! Make sure you use lots of teflon tape, since the iron didn't seem to seal well with the PVC.