Now far be it from me to tell you how to winterize your complete system since every system is different and some need to be completely drained to prevent freezing. Due to that, you’re on your own as far as the plumbing except one important item that seems to get overlooked all to often.... your pressure transducer.
For all of you that have a Variable Frequency Controller running your pumping system and using PID, your system has a pressure transducer that needs to be drained. Some of these are easily done if the plumbing is done correctly with a drain valve and a shut-off valve isolating the transducer from the system. Others of you may need to remove it and let it drain out. If you don't, freezing can ruin the diaphragm inside it and you will need to replace it next season and this is costly. My advice, get it done.
I have a diagram of how I plumb this in conjunction with a pressure gauge. If anyone needs this, drop me a note and I will get it to you.
Regarding your drive.......
If it or they are located outside, a descant bag or two is good to throw in the box to control moisture. Cover the entire air inlet and outlet ports with rodent proof material so your drive doesn't become a winter play ground for them. Shutting down the drive for the winter does no harm if you keep it as dry as possible. The temperature really is not a factor in our area and should cause no concern.
Lock up the box if there is a chance of vandalism. Copper is worth a considerable amount of money and people are desperate. I cannot believe how many jobsites are being preyed upon for the wire. Seems crazy to me but it happens everyday.
Before the next irrigation season gets started, I will post some items to look for and do prior to starting you system back up…. Look for it and if you need or want that plumbing schematic, let me know.