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Custom truck undercarriage with red air horns and air tank

Help Center · Air Systems

Installing The Electric Drain Valve Kit

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

  • What’s in the kit: stainless steel 3/8" solenoid valve, push button, 1/4" NPT × 3/8" PTC elbow, 3/8" NPT × 3/8" PTC fitting, 3/8" × 1/4" reducer bushing, 10 ft of 3/8" air line, 20 ft of 18ga wire, and wiring & terminal connectors
Electric drain valve kit contents laid out

Getting Started

Start by locating the solenoid valve within the kit.

1

Locate and plan the solenoid mount

This valve will need to be installed close enough to the air tank so that you can run the air line to it from the drain port on the tank itself. 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.

Stainless steel electric drain solenoid valve
Locate the stainless steel 3/8" solenoid valve in the kit.

Plumbing

At this point, locate the 1/4" NPT × 3/8" PTC elbow fitting.

2

Install the elbow in the tank’s lowest port

This fitting 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.

Lowest port only: Use a port that faces the ground. A side-mounted drain will not empty moisture.
1/4 NPT to 3/8 PTC elbow fitting
1/4" NPT × 3/8" PTC elbow — this goes in the tank’s lowest port.
3

Plumb the PTC fitting into the valve inlet

Now that you have the tank portion of this install taken care of, move on to the valve. Plumb the supplied 3/8" NPT × 3/8" PTC fitting 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, the valve will not hold pressure and your tank will leak constantly.

The inlet side of the valve can be found by 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 arrow always points towards the outlet on the valve. Take the 3/8" NPT × 3/8" PTC fitting and plumb it into the side of the valve that faces away from the arrow.

Flow direction arrow on the drain solenoid valve
The cast arrow always points toward the outlet.
4

Run 3/8" air line from tank to valve

From here, run the supplied 3/8" air line out to the valve from the fitting on the tank. Simply press the line into each fitting on the tank and the valve.

5

Add the outlet reducer bushing

Now that the valve is in place and the line has been plumbed to it from the tank, install the supplied 3/8" NPT × 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 drain valve kit, and the valve will need to be wired to the push button.

Wiring

The drain valve will be wired to a push button that can be pressed from inside the cab to release the moisture from the tank. The wiring for this valve is pretty straightforward. This valve has two leads that come off of it. It does not matter which wire you decide to use as the positive lead.

6

Ground one valve 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.

Electric drain valve tank plumbing and wiring diagram
Plumbing and wiring overview for the electric drain valve kit.
7

Wire the push button and fused power

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.

Finishing Up

8

Pressurize and test the valve

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

This article provides step-by-step instructions for installing the Electric Drain Valve Kit with dual tanks, covering component setup, plumbing connections, wiring configuration, and final testing to ensure proper moisture drainage.

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