How to Drain Water from a Truck Air Tank?
2 Answers
The automatic drainage device for an air tank generally uses an electronic drain valve, which is installed at the bottom (lowest point) of the air tank. When the air tank is under pressure, gently open the valve at the bottom to release water until gas is expelled. If there is no pressure, the valve can be opened directly. Requirements for installing an electronic drain valve: Before installation, remove impurities such as copper shavings and rust from the air tank. It is recommended to empty the system under full pressure for 35 minutes before installing the electronic drain valve. The drainage direction should align with the arrow on the valve body, and the power supply voltage must match the electronic drain valve's voltage. Precautions for installing an electronic drain valve: The TEST membrane switch on the timer of the electronic drain valve is a manual test button. Each press triggers one drainage cycle. This button is used during routine work to check drainage conditions at any time. The two knobs on the timer adjust the drainage duration (how long each drainage lasts) and the interval between drainages (how often drainage occurs). The small screw on the wiring box of the electronic drain valve not only serves as a connection but also compresses the sealing gasket to prevent water from entering the timer and coil. Therefore, it must be tightened securely.
I'm a seasoned truck driver with 15 years of experience since my twenties. After every long haul, I make it a habit to drain the water from the air reservoir. Moisture accumulates in the truck's air brake system and condenses into water, so the small drain valve at the bottom is specifically designed for this purpose. When draining, I first park the truck securely and ensure the engine is off – operating with high-pressure air in the tank would be dangerous. I usually use my hand or a small wrench to gently open the valve, hearing a hissing sound as water slowly drains out until only clean air remains, then tighten the valve again. This maintenance is crucial because accumulated water can corrode the tank and lead to brake failure, especially for trucks operating on mountain roads. Since adopting this routine, my truck's reservoir has lasted seven to eight years without issues, saving me repair costs. I advise new drivers not to skip this – just do it after every unloading. For me, it's become as natural as brushing teeth – simple yet reassuring.
