speaking of winterization, I got a client's system winterized today. I think it was a sweetwater system with the glass jars covering external filter and the check valve at compressor,(not what I use), anyway, when I opened the lid I found out what the suction from the pump through the checkvalve will do to a field mouse. I wish I had a digital camera to show the sadistic people out there. I could still see his nose and tail. A good reason to put the check valves at the diffuser.
Robert B