Since accumulator tanks are pressurized they should self drain when the drains are opened. Suspect it doesn't hurt to have them in a vertical mounted position to ensure draining.
Thank you. Will ask for that.
Actually, the accumulator drains out 99.99999% of the water regardless of the orientation.
Think of it like this.
- Imagine a glass jar filled with water.
- The lid on the jar has two holes.
- Place a large balloon inside the water-filled jar with it's end passing out through one of the holes in the lid.
- Blow air into the balloon.
- Water shoots out the other hole.
- Keep blowing in air until the balloon completely fills the jar.
- 99.99999% of the water is now out of the jar regardless of orientation.
An accumulator is just that. With it pre-pressurized to the right PSI inside, you can see the balloon called a bladder, inside pressed against a perforated metal grate-like screen. That screen prevents the bladder from popping out the opening. The shape of the tank and bladder together assures that all the water gets forced out. Any residual water remaining inside the accumulator is exceptionally minute with no concern of freeze damage.
I would let Phoenix determine the best orientation of the tank in the limited space they might be working with.
If your PC has room, I recommend a 2 gallon tank. We have a 2 gallon tank and it's pump-cycling intervals seem perfect. When full, the tank holds roughly one gallon of water and one gallon-volume of compressed air. I am really guessing wildly on a 50/50 air to water ratio, stated only to help visualize how it works.