HP Davv Portable High Pressure Air Compressor Paintball Scuba Dual Piston Pump

I think a few people on this forum have or had that type compressor. You will probably hear from them. It looks very much like an evolution of the Yong Heng, external cooling and many other "similarities". I'd ask how much they cost and does it fill faster than the Yong Heng.

Looks like a derivative of the tuxing from China. Personally I don't like direct drive compressors they most likely turn at 3600 RPM or best 1800 RPM. Most are from China with motor is really designed for 50 hertz so they are turning higher RPMs and they are designed for. Of course everything has trade-offs direct drive is less expensive at the expense of longevity.

The single cylinder Davv branded pumps were around before the Yong Heng came on the scene. This twin cylinder model looks like a very basic generic Chinese made pump. Being basic is not a bad thing, having less features means fewer things to go wrong. I assume that it would have the same issues as the other cheap Chinese alternatives but would probably give quicker fill times than the single cylinder jobs.

That looks exactly like the main component of my hatsan lightning. Same as the air venturi 4500 compressor.

It looks to me, like a direct driven, Carette/Kalitte. If it is, even though it may look like 3 stage, the second cylinders piston has holes in the top, and only serves as a platform for the high pressure piston (rod). So, it has no more than a Yong Heng type. I have a DAVV 4 cylinder radial, I bought off Amazon. It is working fine, so far. I just re-built my Carette/Kalitte, and it is also working OK. I want to plumb in a water line from my home system for cooling, and route the exit line out to the garden. Just turn on a vale when running, and a continous supply of cool water. No buckets, fans or radiators. Except the DAVV 4 cylinder is air cooled by a large fan blade.

I think a few people on this forum have or had that type compressor. You will probably hear from them. It looks very much like an evolution of the Yong Heng, external cooling and many other "similarities". I'd ask how much they cost and does it fill faster than the Yong Heng.

Click to expand...

I own this pump. I like it. The cylinder on the left if for low pressure, and the cylinder on the right is for high pressure. It's a 2 stage pump.

Now that's not to say I haven't had a learning curve with it. Here's what I've learned through trial and error. Don't run the pump for more than 20 minutes at a time. Let it cool and relax a bit between pumping cycles. They will send you a complete kit of replacement parts for it with the purchase. The one thing they won't send you are spare pistons. The proverbial "weak link" of this compressor is the piston on the high pressure side. It's basically similar to the dual functioning piston of the Yong Heng single cylinder compressor. If you push the piston too hard, the brass rod with the teflon split rings that seal in the HP cylinder wall with crack the top of the aluminum piston it's attached to. I speak from experience. So DO NOT exceed 4600 psi with the compressor. Also, run the air through a filter before it goes into your CF scuba tank, or your 480cc air rifle tank. The air is heavy with petroleum smell. So I run mine through a filter that has desiccant, cotton, and charcoal. Does a good job of giving me clean, dry air. 

On my 90cu tank, I can go from 3800-4600psi in about 17-19 minutes. It pumps fast! Also, Don't turn off your compressor with the pressure at 4500 psi. Bleed off the air while the compressor is running. Shut the valve on your tank, and immediately turn the drain valve on the compressor while it's still running. This prevents the piston from slamming down with an instant cut off from power. I actually made a male foster to male foster one way HP check valve that goes between the compressor and the dive tank. I attach it to the female foster fitting on the air hose from the tank, open the valve, and the pressure from the tank shuts the valve. Then when the pressure from the compressor regulates with the pressure in the tank, the valve opens and the air starts to flow into the tank. No guessing about when to open or close the valve on the dive tank. Also, when you bleed the air from the compressor, and it drops below the pressure in the tank, the valve shuts again. So you don't need to have to rush to shut off the compressor after shutting the valve on the tank. You just close the valve on the tank, and the only air you're bleeding off is the air trapped in the HP fill hose connected to the tank.

I have LOTS of advice with this pump. Shoot me a PM or email if you want more.

Cost? Fill time seems similar to the YH. Also externally cooled like the YH. The main functional difference seems to be that you have a separate cylinder for 1st and 2nd stages on the DAVV while these are combined into one cylinder/head assembly on the YH. Again, I'd ask about cost (closer to YH or nearer the Omega line?) and how long term reliability shakes out.

How do you drain the oil? Do you remove the crank case cover and then re-order/replace the rubber crank case membrane?

Odd... even my Yong Heng LPA compressor from way back when has an oil drain bolt.

Good to see self contained water cooling on that second linked version for not a lot higher cost. Should give people another option in the sub $1000 price range.

Regular compressor oil is not recommended. The oil from Home Depot is for compressors that only reach 120/150 psi, not 4000 psi. The "good" stuff ain't cheap either...

https://www.nuvair.com/products/parts-accessories/oil/oil-coltri.html

I just bought the same upgraded model. And my fill hose leaks right at that the the oil/water separator where it screws in.. have you had this problem? What do you recommend I can do to seal it right there?