[SD Formula]

Originally Posted by mrennie

Hi:

When you say the drain valve is connected to the line at the top of the tank, do you mean the line attached to the unloader valve? For the drain valve to work properly, the "signal" line has to be connected to an air source that goes from 0 psi to full pump pressure and back to 0 psi as the pump cycle starts and stops.

I have found with the valves I have that they stay open longer when the pump shuts off than they do when it first comes on; when the pump starts, they open for maybe 1/2 a second, but when the pump shuts off, they stay open for maybe 3 or 4 seconds. They don't cycle exactly the same either; onbe o fthem stays open alot longer than the other, possibly due to a variation is internal dimensions (made in China!!)

Note that the way the valve doesn't actually just open and close; there is a slug inside with an o-ring at each end and when the pump comes on it slides to one end of the valve body, and when the pump shuts off it slides back. As the slug moves from one end to the other it unblocks the high pressure port from the compressor tank and bleeds off air and water.

Several times over the past year I have had a problem with one or the other o-ring popping off the valve and the valve starts to leak, but that doesn't seem to be an issue for you.

For the water trap you built, the air should enter at the side near the bottom, and the air exit should be at the top. The goal is to slow the air down so the water droplets being carried by the air will drop out of the air stream by gravity and settle in the bottom 8"-10" of the trap. If your air enters from the top and exits at the side near the bottom, it will be easier to carry water droplets with it and won't be very effective.

The air connection from your tank to this trap should be fairly large; using a 3/8 flex air hose is too small, and will be a bottleneck for your system. If you have a true 5 hp motor and an 80 gallon tank you probably have a 2 stage pump running 16-18 CFM and ideally you would connect the water trap to the tank with a 3/4" line for least resistance.

If you have more questions fire away!!

I should have been more clear on the line connections. I installed the brass tee in the unloader line at the top & installed the HF valve in the drain line at the bottom. I have had the valve apart & it looks clean & moves freely. Yes my compressor is a two stage, It turns on at about 125 psi & shuts off at 175 psi. If I use the second HF valve in the botton of my 2" pipe water trap & add a second tee in either the unloader line or the copper line that I added, I'll be using the same air pulses to control both valves. I think this is the arrangement that you have used?? If so how is that working? You mentioned that one valve stays open longer than the other. Further thoughts on the 2" pipe connection, If I connect the pipe to the tank at the lower side directly with, as you suggest, 3/4" pipe, I would probably be pulling out cooler air (at least initally) than I would be getting from the top side tank connection. This might be more desirable for condensing the water from the air. Any thoughts on this?

[SD Formula]

Originally Posted by Birdguy

I also have some experience with the Harbor Freight drain valve, and it's not very positive. The first thing to go was the crappy black plastic tubing coming off the unloader valve that blew out the first time the compressor cycled. Next I ran copper from the upper tee down to the valve under the tank.

What I have observed is that it seems work just fine initially. Over time the condensed water and oil seems to want to back up into the valve and render it useless, even with me manually draining the tank periodically. The only thing I can think of is that the cycle time for the valve is too short and not enough gets expelled when the compressor cranks up and shuts off. At least that's my experience.

I ditched the plastic HF line right away & went to copper. I've had similiar problems with the previous drain valve that I used. I used one that opened automatically when the compressor had little or no air in it. This meant that you had to totally bleed off all the air to get the valve to open, this was only slightly better than kneeling down & manually opening a drain valve. Eventually the valve would leak from all the crud buildup in the valve. It seems that a large portion of the hours on my compressor involve bleeding off the air to get the water out of the tank. In addition, to leaks that cause it to start up in the middle of the night because I forgot to close the air valve. Thanks for your input.

[mrennie]

Originally Posted by SD Formula

If I use the second HF valve in the botton of my 2" pipe water trap & add a second tee in either the unloader line or the copper line that I added, I'll be using the same air pulses to control both valves. I think this is the arrangement that you have used?? If so how is that working?

Yes, that is exactly what I am using and it works fine, except as mentioned, the 2 valves don't stay open for the same amount of time. The one on my water trap closes about 1-2 seconds before the one installed on my air tank.

[mrennie]

Originally Posted by SD Formula

Further thoughts on the 2" pipe connection, If I connect the pipe to the tank at the lower side directly with, as you suggest, 3/4" pipe, I would probably be pulling out cooler air (at least initally) than I would be getting from the top side tank connection. This might be more desirable for condensing the water from the air. Any thoughts on this?

I don't think it makes too much difference whether the exit point from the air receiver to the water trap is near the bottom or top of your tank, but you should try to take the air off as far away as you can from where it is going into the tank.

Ex., if the pump puts air in on the top right, then taking air out in the bottom left should result in less water carry over.

The warm moist air enters the tank at a decent velocity from the 1/2" or 3/4" line from the pump, and the air velocity slows down greatly as it travels through the tank since the tank is so large. This slower moving air allows the water droplets to condense and drop out to the bottom of the tank.

[BILTIT]

Best option i think is having the compressor line going into the side of the tank and pulling air out the top. This is the arrangement on most water/gas seperators i see.

I will have to reference this thread when i do my system. I am running all stainless steel tubing (1/2 or 3/4'') around my shop and will be bending it myself. I might use copper for the cooling coil right of the compressor though as it conducts heat better than stainless.

[SD Formula]

I can't (I could but with much difficulty) really remove the air at the top of the tank, that is where the inlet from the compressor & the unloader valve are located. Currently the air is drawn out the side of the tank ~10" below the top inlet. There is another possible outlet on the same side of the tank ~36" from the top inlet, that I could use. If I pipe the air out at the bottom side outlet it will be quit a bit further from the inlet & cooler. Sounds like I should go for the bottom side outlet?

[mrennie]

If not too much hassle, I would connect to the farther outlet. If a PITA, maybe try the easier outlet and see how much water the water trap picks up. If the trap is picking up water and there isn't noticable water at your tools, you are doing well.