I've pretty much completed my tandem air compressor-air dryer setup, and will post some pictures of it once perfected. For both my 3 HP 60 gallon and my 1.8 HP 30 gallon compressors, I took the compressor output and ran it through an a/c condenser, through a water trap (old compressor tank) and back into the main tank. A fan blows on the condenser and cools the air by about 100 degrees F before it re-enters the main tank. The condensed water stays in the trap/tank, and very cool, dry air goes into the main tank. It works very well.

Both compressors are hook up to my shop air line, and I set them to turn on at different pressures. The 1.8 HP is basically an booster for the 3 HP.

Here's my challenge. Because I essentially spliced the dryer contraption into the middle of the pipe that went from the compressor head to the in-tank check valve, the unloader valve bleeds the air from not only the compressor head, but also the water trap tanks and a/c condensers. It hisses for a very long time before shutting off. It still works great, but I'm essentially wasting electricity and scaring my chickens.

I know I need to place an inline check valve probably right after the compressor head, but I'm not sure how to handle the unloader valve. I like for the condensers and water trap tanks to remain pressurized and just unload the compressor head.

Any experts have an solution? I've seen a couple of these deals on youtube, but I couldn't tell how they were setup.

I haven't experimented with this myself, but the condenser and water trap are essentially now replacing the single pipe from the head to the tank...so is there a way to move the unloader valve to the input side of the condenser?

chris wrote:I haven't experimented with this myself, but the condenser and water trap are essentially now replacing the single pipe from the head to the tank...so is there a way to move the unloader valve to the input side of the condenser?

I think I've figured it out. The unloader valve on both my compressors is actuated by the pressure switch...that's the critical piece of info that I needed. I think I need to remove the tube from the in-tank check valve and plug that hole, then add an inline check valve (two on order from ebay) between the condenser and water trap, then add a tee fitting upstream of the inline check valve and connect the tee to the unloader valve. This should bleed the air from the compressor head and the condenser, but leave the water trap tank fully pressurized.

The challenge I'm having now is that I need a barbed branch tee fitting that has 3/8" barbs and a 1/4" compression fitting on the branch side, and one that has 1/2" barbs and the 1/4" compression. I've searched McMaster-Carr, Grainger, eBay, and the entire WWW looking for them. No luck with the exact type. I'm probably going to have to build a Rube Goldberg device from the brass fitting department at Lowes.

Got my QC3 water filter installed with an additional water separator upstream of it. Now I just need to get some DeBliviss high-flow connectors and a 1/2" hose. I don't think an ample supply of clean, dry air is going to be an issue when I paint my truck.

Sounds good Nate - let us know how it goes. I think you have it covered!