Electric Drain Valve Kit Components


  • Stainless Steel 3/8" solenoid valve (D)
  • Push Button (H)
  • 2x 3/8" NPT x 3/8" PTC Elbow Fitting (A)
  • 1x 3/8" NPT x 3/8" PTC Fitting (B)
  • 3/8" x 1/4" Reducer Bushing (E)
  • 10 Feet of 3/8" air line
  • 20 Feet of 18ga Wire (Blue roll above)
  • 3/8" PTC Union Tee (C)
  • 4x 18ga. Butt Connectors (F)
  • 18ga. Ring Terminal (G)

Getting Started

Your electric drain valve kit will allow you to drain the moisture from your tanks from inside the cab with the push of a button.

Start by locating the solenoid valve within the kit.


This valve will need to be installed close enough to the air tanks so that we can run the air line to it from the drain ports on the tanks. The moisture will dump from the outlet side of this valve so you may want to point it down to the ground so that it isn't spraying towards the vehicle.


At this point, you will want to locate the 3/8" NPT x 3/8" PTC fittings. They should look like the image below:


These fittings MUST be plumbed into the bottom-most port on the tank. This is not always the port in between the legs of the tank. If you mount the tank sideways, this fitting would be plumbed into one of the ports facing down to the ground. This is essential for this kit to work, as gravity will pull the water to the bottom of the tank over time. If this fitting is mounted on the side of the tank, no water will come out when you press the button.


Now that you have the tank portion of this install taken care of, move onto the valve. You can now plumb the supplied 3/8" NPT x 3/8" PTC fitting (B) into the inlet portion of the valve. This is important because the valve is directional. If you plumb the inlet fitting to the wrong side, this valve will not hold pressure, and your tank will leak constantly. The inlet side of the valve can be found by simply looking at the valve itself. Cast onto the valve is an arrow. The airflow needs to go in the direction that the arrow points. The image below shows where you can usually find the arrow on these valves:

Flow Arrow - 1/2
Outlet & Inlet Diagram - 3/8

In this image, the arrow points towards the outlet on the valve. The arrow ALWAYS points towards the outlet on the valve. Take your 3/8" NPT x 3/8" PTC fitting and plumb it into the side of the valve that faces away from the arrow. At this point, you can now run two lengths of 3/8" line from each tank into our tee fitting. We recommend using two 3' sections of line for this connection. Plumb each line into tanks 1 & 2. Plumb the opposite ends of each line into the tee fitting as shown below. Tanks 1 + 2 will plumb into the sides of the tee, and the middle portion of the tee will be used to connect the tee to our valve. Cut a section of 3/8" line to go in between the tee fitting and the valve. Plumb the line into the tee, and then into the valve at the opposite end.


Finishing Up

Now that the valve is in place and the line has been plumbed to it from the tank, we can use the supplied 3/8" NPT x 1/4" FNPT reducer bushing into the outlet portion of the valve. This will slow down the flow of air out of the valve so that you don't lose all of your air in the tank. At this point, you are done plumbing the electric drain valve kit, and the valve will need to be wired to the push-button.


The drain valve will be wired to a push-button that can be pressed from within the cab to release the moisture from the tank. The wiring for this valve is pretty straightforward and shouldn't take to long to finish.

Electric Drain Valve Kit Wiring Diagram

This valve has two leads that come off of it. It does not matter which wire you decide to use as the positive lead.

Take one of the leads and route it over to the frame of the vehicle as a ground. Alternatively, you can run this to the negative terminal on the battery. The opposite lead can be run up to one lead on the push-button. Finally, take the opposite end of your push-button and route it to a fused power source capable of handling a 10A load or greater. If you are installing this drain valve with one of our kits, you could simply tie it into the same fuse connected to your battery that supplies the compressor with power. Once connected, press the button and listen for a 'click' from the valve. The clicking sound indicates that it is working properly.

Start your vehicle and pressurize the tank. You can test this valve by pressing the button a few times and checking to ensure air escapes from it when the button is pressed.

Your electric drain valve kit is now installed and ready for use!

Next up: Installing the Digital Air Pressure Gauge!