I did the same thing with my compressor a few years ago. However, I wired the automatic drain timer in to the run side of my compressor motor contactor, so that the drain timer is only active when my compressor is running. This does not waste air pressure and keeps the water out of my system.
I think I would tie that power switch on the tank drain into the circuit when the compressor kicks on. Then set the auto drain to every 1 or 2 minutes (While the compressor is running). Then set the drain time to maybe bleed of a couple short bursts like every few seconds or so. That way, everytime the compressor starts, so does the auto drain switch. When power goes off on the compressor switch, it also shuts off the auto drain switch.. Then, it's not popping off every 45 minutes during every 24 hour day. I don't know why the timer is only a max of 45 minutes....should be hours or days, not minutes.
I started taking careful notes to implement this for my air compressor, only to learn that PEX degrades rapidly when exposed to UV light (e.g. sunlight). Apparently latex paint can be used to protect PEX, but I'm going to use copper, PVC, or something else tolerant to sun exposure for the exterior parts.
I ended up using black pipe, since the exact length I needed was available pre-cut/threaded, and all the necessary adapters/fittings were easy to find.
That timer switch for the compressor is genius. I was just thinking about something like that to prevent accidentally running my compressor if the drain valve is stuck open, or prevent burning out the pump
Does an automatic drain valve allow you to keep your tank full all the time so you’re ready to go anytime without having to refill the tank from empty? If that’s the case, wouldn’t you want the drain valve on all the time instead of wired to the motor run only when the compressor runs? Just trying to learn before I purchase one.
If you wired it to the wall, it would eventually drain all the air from your compressor or cause it to run since it purges air every time. You could wire it into the pressure switch but I'm not sure if the valve would work with 220v or not.
