PneumaticPlus SAD402-N04D-MEP Compressed Air, External Water Trap Valve with Automatic Drain 1/2" NPT - Metal Bowl Sight Glass, 10 Micron

I replaced the original auto water drain on my Harbor Freight Compressed A/C Dryer. Same 1/2 pipe thread connection on the top. Works properly ever since the replacement several years ago. The original drain was junk, didn't work from the beginning and was leaking. Highly recommended to replace yours for trouble-free operation.

I purchased this auto drain to replace the original auto drain on a Harbor Freight air dryer. The original did not work correctly. This replacement works as it should and seems to be of good quality.I would recommend this to a friend.

The Harbor Freight Air Dryer in and of itself is a good deal and works well, but the Automatic Drain Valve it comes with is complete junk. Works for about a week. If you buy a HF unit, get one of these SKP traps, too. Replace the old one before you even turn it on.Save yourself the headaches......

For refrigerated air dryer... Appears to work. Rain and high humidity ATM.

Product rusts internal with the exposure to water. have broken 2 so far in over a little over a year.

My system does not generate enough water to put it thru its paces. Seemes well built. Would buy again. good price.

I share a shop with others, came into the spot long after the pneumatic lines had been run… The setup is chaos, many low spots in the line where water gets trapped etc. My station is the first out of the compressor and the lowest spot in the system… I used to come in every day with a hose full of water but after installing this I don’t even get any midst.- t’s not designed to get hot imo, make sure you cool the air before it gets to this unit.- If your lines are full of rust and scale it probably won’t last as long as it could in a clean system. Mine has been going for 8 months now (rust free system)- Keep it away from vibrations, being bumped etc.-When the line has low to no pressure, the drain is open. As the line is steadily pressured, the valve snaps closed. (I don’t know if it can auto drain if you never depressurize the line)

I had a problem controlling the moisture in my compressor air lines before installing this unit which saturated my desiccant filter rendering it useless as well as letting moister get to my air tools. I am happy to say I have had no problem since installing it.