Has anybody checked these out yet"3500hours before maintence?

O.K., if anyone is still following this thread, here are my final thoughts on the Diablo HPA compressor for today.

I am going to keep it. Haven't heard back from eBay seller yet, but I've now got a whole afternoon invested in this compressor. It continues to make pressure and I think it has potential, albeit with some cheapness to the design/assembly/components.

I had a totally empty 500 cc eBay bottle, so I put it onto a gun and filled from zero to 250 bar. I didn't time the fill, but it probably took 5 minutes or less, and the compressor finished off the fill at a very reasonable temperature of 54.1C. It was no speed demon - but was maybe only slightly slower than my Benjamin ReCharge. Much faster than any of those little cheap 'chucka-chucka' compressors I have tried (think Umarex ReadyAir type). The needles on the compressor's and gun's gauges just rose slowly and continuously until pressure was achieved, and it looks like they were reading within maybe 5 bar of each other at 250bar.

I do want to make some changes to it. I took apart the pump and when I re-installed it it now just sounds like a loud pump motor, but not like it did before. Nothing of substance to be found inside it. It did show some dirty areas inside, residue like if they tested it with dirty water at the factory, and then just let it air dry. But no chunkies or large debris. The pump head attaches to the pump motor with 2 screws, and the pump motor has a dual-lobed head which works the pump. There was some grease in the interface and I put a little more in. Maybe even more, or a different type of grease would quiet it down more. But in the end it is nothing other than a little 12 volt pump, which is likely easily and cheaply replaceable. Nothing special, and if I replaced it I might even install it on the outside of the panel instead of the inside. Not as pretty and clean, but better for functional access.

The cooling system on this compressor may just be an afterthought, or significant cost cutting was undertaken by the builder. Soft silicone hoses are in direct contact with metal which will get hot, and in some cases in contact with the edge or corner of a metal piece. I'll probably protect those contact areas, maybe with a piece of bicycle innertube wrapped around the coolant hoses. Ultimately I'll just get some more silicone hose, and replace the OEM hoses with longer pieces which I can route more intelligently.

Also interesting to me that the oil level sight glass (plastic) also seems to be the oil drain plug. There is no other drain plug as I have become used to on other compressors, and the sight glass has fittings on it for a hex wrench or socket. Workable, I guess.

Morning update, after some conversations with eBay seller:

1) They misread or didn't fully read my message to them. They thought that I was only having issues with my 'can full of rocks' sounding coolant pump, and suggested that I check the electrical connections since they sometimes get loose during shipment. Oh well.

2) They specified that they had replacement parts for these compressors, and that they could fully support buyers.

3) But when asked about a replacement for the faulty coolant pump they said that they could ship me one for about $100. WTF?

4) I replied that I didn't think it was fair to charge for a defective part. I asked if they would refund $20 from the purchase price so that I could purchase and install a new coolant pump. They agreed to do this.

5) I asked if they would be listing more of these compressors on eBay, or for sale directly. They responded no, that the ones they sold were 'excess inventory', had an original MSRP of $1,500 and an original wholesale cost of $750. They continued by saying that they had 'a few more left.'

6) I have purchased a replacement coolant pump off Amazon. Easy to find in virtually the exact form factor ("12v sprayer pump"), with costs ranging from $13-$30+. 

7) I also purchased 10 feet of 3/8" x 1/2" silicone tubing so that I can re-run my cooling lines to keep them from contacting potentially hot/sharp parts of the compressor. Easy to source this tubing as apparently it is widely used for home beer brewing equipment.

I continue to feel that for the price paid, this is a great value for a capable home HPA compressor. Of course my vision may be clouded as this is a brand new toy for me, and is currently working. And as Odoyle likes to remind us, folks are generally really pleased with their inexpensive China compressors after the first few successful fills, but are not so happy when they become expensive doorstops after breaking down in 6 months. Hopefully I can get a good service life out of this Diablo unit if I treat it well.

been watching for a update on your purchase ?

Mine is now in daily service at home, and is still performing as it did when new (at least after it eventually started making pressure). I use it to top off a few guns a day, and have topped off a couple of larger bottles as well. First oil change was at 1.1 hours, and the anticipated small metal specs from break-in were seen when holding the oil in the sunlight.

It is not a fast compressor but it cranks along and gets the job done. About 2.5 hours of run time now on mine, which includes about 30 seconds running before I close the bleed valve and start to fill, and about another 30-60 seconds when fill is complete and I just let it run to cool down with the bleed valve open, before I turn off the compressor and let the cooling system take the temp down the rest of the way.

I have determined that the type of pump the manufacturer used for the cooling system (diaphragm type) is just darn noisy. I did replace the original one with one of the same form-factor and pumping capacity I bought off Amazon. It is quieter, but not quiet. I tried a small centrifugal pump which was almost silent and actually had a higher specified flow rate, but for some reason it seemed to me that the overall effectiveness of the cooling system was reduced (reached higher temps when filling). So I reinstalled the diaphragm pump.

I have all of the air leaks stopped, which may have occurred during sloppy assembly and/or shipment. I don't really like the design of the bleed valve but it doesn't seem (to me) to be very easily replaceable, so I continue to use it. The PTFE seal used is not your typical flat disk, and when I tried to use one (flat disk) at first it seemed to work but eventually wouldn't hold pressure over 200 bar. Unfortunately with the OEM bleed valve you don't seem to get that big rush of air out the vent hole when you open the valve, but instead air escapes along the threads of the bleed screw, slower and less effectively. So while I normally can open the bleed valve, allow the compressor to continue to run and cool down, and unhook the fill probe from the gun, the way my OEM system is working there is still too much pressure in the line. So I have to wait and unhook the fill probe after I shut down the compressor. You also have to crank the bleed valve closed (by hand) a little more than you might be used to on other compressors, or pressure will not build.

My unit is now really ugly, but the ugliness should allow longer service life. From the manufacturer there are too many wires, flexible pressure lines and coolant hoses laying against metal parts which may get hot and cause wear from vibration when the compressor motor is running. So I have zip ties all over for lines to 'float' instead of rest against hot, vibrating metal. And pieces of old bicycle inner-tube wrapped around wires and lines in metal contact areas.

Would I buy one again, knowing what I know now? For the price these sold for, yes I would. But this compressor is definitely not for someone who wants "plug-n-play" or a high level of vendor support.

I don't like everything about how these were built, but generally it works just fine. And its cooling system is probably the most effective I have seen on a home HPA compressor (as opposed to a Club or Commercial one). And to me an effective cooling system is likely the most important aspect to obtaining a reasonable service life. 

This compressor has also helped me learn more about home HPA compressors. And for its price I am not hesitant to experiment with some different components. I have already referenced the changes I made to the coolant pump. I am also thinking about possibly revising the whole manifold which contains the bleed valve. It will be doable with inexpensive components, but for now it is working so I'll leave it alone. Of course this is not something I would ever contemplate on a $2,000 compressor.

One additional hint to new owners of this compressor.

The main cooling fan sucks air in, from the outside, over the cooling blades of the radiator, and then back across the compressor motor and compressor.

The volume of air it is moving when operating makes leak checking difficult.

But it is a simple 12 VDC fan and has a quick-disconnect plug in its wiring.

When checking for potential leaks with the compressor running, unplug the main fan and your leak-check solution will not be blown off the HPA fittings.

But don't run it too long in that state and be sure to check your temperature gauge regularly!

Good read, hope it gives you years of service. If they stock repair parts for these I hope they are at a better price than what they wanted for the water pump.

It seems like a lot of the parts are pretty standard stuff, and what I can standardize further I will.

The bleeder valve, for example. While the OEM PTFE 'cup' type seal on the right side of the photo seems unusual to me, I decided to try an experiment. I took a standard flat PFTE seal ring (left side of photo) and put it into the manifold. Then I took a standard steel BB and put it into the end of the brass threaded bleed valve body (held it temporarily in place with some thick/sticky o-ring lube). Screwed that in and seated it on the PTFE disk, and then screwed in the bleed screw. Seems like it didn't need as much force on the bleed screw to get a seal, and I ran the compressor with a dead-headed fill whip up to 300 bar a couple of times with no leaks. And when cracking open the bleed screw, I now get the desired rush of pressurized air out of the hole on the right side of the manifold.

Then I filled a gun which I was going to shoot tomorrow, but it is only a Hatsan so it only fills to 200 bar. But it filled fine, and the pressure bleed worked perfectly.

If it continues to work, then I have just standardized a couple more parts on the Diablo.

Anyone who buys a made in China compressor is making a mistake using automotive motor oil as a lubricant. Here's why.

Automotive motor oils contain detergents which suspend and emulsify dirt and debris which get filtered out by the engine oil filter as it circulates. Automobiles are pressure lubricated. That's why you have an oil pressure gauge on your dashboard. Most air compressors are splash lubricated. A dipstick is attached to the bottom of the piston rod that splashes the oil upward to lubricate the pistons. The bottom of the crankcase collects sediment. There is no oil filter. Therefore when a user buys motor oil he is not allowing the trash in the oil to settle. The detergents, metal shavings, dirt, etc. are collecting on the pistons and check valves. I rebuilt an Air Venturi similar to the compressor in this thread. It wasn't building pressure beyond 3K psi and the high pressure check valves were totally clogged with burnt oil deposits. The bottom o-ring seal was broken and a third of it was missing. The upper two seals were worn and leaking once pressure reached a certain level.

All of this wear and tear would be greatly dimished by using the proper non detergent high pressure compressor oil. Notice that most China compressors come with a one year warranty. The one in this thread has only a 90 day warranty. Why? After 90 days you pay for repairs or throw it away and buy another one. Protect your investment by using the proper lubricant. The few extra dollars you spend on oil is insurance against spending it to buy another compressor every year or on shipping and replacement parts needed from using the wrong oil. 

I wonder if they recommend motor oil so they can sell replacement compressors? Hydraulic fluid is just as bad as motor oil. Follow Chinglish instructions at your own risk.

 "A dipstick is attached to the bottom of the piston rod that splashes the oil upward to lubricate the pistons. The bottom of the crankcase collects sediment. There is no oil filter. Therefore when a user buys motor oil he is not allowing the trash in the oil to settle."

And this is exactly why I believe that a more frequent lube change regimen can be helpful on these type compressors. Even using the best compressor lube, the "sediment" that you note is still somewhere in the crankcase because there is no filtration builds up. It's fine to assume that it settles to the bottom and stays there. Might be true, might not. If it is being mixed back into the lube from the "dipstick" movement and compressor vibration each time the compressor runs then removing it more frequently would seem to be advantageous. It has nothing to do with "life expectancy" of the lube itself as it might be fine for longer but if full of "sediment" then that can be a problem. A small volume of lube to change each time and more frequently sure seems like a bit of added prevention to me. For the YH I've used for over 2 years, I remove the cover every few lube changes and clean out the "sediment" that is present. And there is always some present that doesn't drain out with the lube, every time.

thanks for the reply TMH...

thanks for the reply TMH...

Click to expand...

But wait... there's more!

Short story: eBay seller refunded my money when my compressor failed, and said to keep it. I may be able to repair it better than OEM for very little cash.

Long story: read on.

My compressor stopped running last Friday. The ancilllary (12 VDC) systems still ran (coolant pump and main cooling fan), but the compressor would not run at all.

I am by no means an EE nor an electrician, but I have some experience with electrical systems. I traced voltages all over the system and found 110 VAC where it should have been, and 12 VDC where it should have been. Nothing was obviously burned or anything (more on this later). I probably spent 8 hours trying to troubleshoot to no avail.

I initiated a return for the unit through eBay. By Saturday morning the eBay seller had issued a complete refund, adding a note to 'just keep it'. These compressors are obviously not their main line of business. They likely picked up a bunch of them cheap, maybe at a bankruptcy auction or something, and figured that they could make some money off them.

So I had a free compressor to play with. I started off by stripping all of the safety interlock circuitry (electro-mechanical relay which allowed the compressor motor to run only when the cooling system was already running, and a 70C thermal shutdown). I got to the point where I hooked up the AC wires from the black 'tub' sitting on top of the compressor motor directly to a wall cord, and plugged it in. And the compressor ran fine! I had thought that the safety interlock system was the culprit, or maybe (worse case) it might be a stuck brush on the compressor motor. But the motor seems fine.

Now color me stupid. One should ALWAYS start with the most simple components when troubleshooting a system. I did not. When checking all of the components again after I had stripped them off the compressor, I think I found my failed piece. The main compressor switch - which you can buy on Amazon for $5 a pair, had apparently burned/failed internally. When checking voltages the day before I was using the input side of the switch instead of the output side of the switch as my test point, and totally missed this failure. D'oh!

And now the story gets even more interesting. After I purchased mine another AGN member traded some PMs with me as he was on the fence about purchasing one. He eventually did, and his ultimately failed after a couple of days use. In his case the electro-mechanical relay and its socket kind of burned/melted. As we speak, the 'clean' components from my Diablo are winging their way to him via USPS for his Diablo. And when he contacted the eBay seller, they responded with 'Just keep it and we'll send you another one.'

Once again, I am not an electrical whiz by education or training. When I looked up the part number of the OEM electro-mechanical relay, it appeared that it could be triggered by AC or DC voltage (both had the same part number?), and it had a 10 amp rating. And I know that my OEM compressor switch was wired with AC voltage, and had a 16 amp rating. I think that these component ratings are acceptable when everything is running fine, but leave little room for error. Like if something caused the compressor motor to start up slower than normal. When a motor is just starting up it draws the most current and if it starts up too slowly the current can spike through the roof. That leads smoke and bad odors in the room! (It was an old joke with Lucas Automotive Electric Systems ('Lucas - Prince of Darkness') that you would need to replace your wiring harness if you ever 'inadvertently allowed the smoke to be released from the system.' Some clever person even came up with their own repair kit.)



I think that in the end we will wind up with functional compressors at low or no cost. I have parts ordered for less than $25 from Amazon which I will install to make the electrical system much more robust. 

The first is a replacement main compressor switch (2 for $5)! The second is a $9 40 amp DC triggered AC relay. I went with a 40 amp model over a 25 amp model as the price difference was a buck. (The wiring will be able to take in excess of 25 amps, the Diablo has a 25 amp internal circuit breaker, and the wall plug is likely a 15 amp breaker, so all will be safe). I will utilize the Diablo's existing 12 VDC power supply (which powers the coolant pump and main system fan) to trigger the relay. So the safety protection (compressor motor will only run if cooling system is running) will remain in place. And the main compressor switch will now switch only low current DC voltage.

The biggest difference will be that the Diablo's electrical components will now have a higher amperage rating, and be more modern & robust for a longer service life.

During the down time waiting for my Amazon orders to be delivered, I re-routed and sheathed my coolant lines for protection, as well as moving both the coolant pump and the OEM AC/DC convertor/power supply to the outside of the Diablo's frame for easy future access. And did the second oil change (2.3 hours of run time). My new electrical components should be delivered tomorrow so that I can finish the project.

So I should end up with quite a nice little compressor for a total of maybe $25 in parts, and my time and labor (which I determine to be of zero value, since I'm retired ).

Oh, and the other AGN member who I have been working with also pointed out that the main compressor components of the Diablo compressors appear to be identical to systems sold on Amazon under the 'HPDAVV' brand:

https://www.amazon.com/HPDAVV-Controller-Compressor-Accessories-Operational/dp/B07HKJ4SCP/

The control and cooling systems appear to be different, but this company could be a future resource of compressor rebuild parts if/when needed.

I really kicked myself when I had stripped out all of the electrical components when it was only a cheap and easy to replace switch which had failed. But when I saw photos of the other member's unit with its burned out components, in the end I was glad to be replacing the OEM control system with something more suitable.

And the Diablo HPA compressor saga continues.

More of the Diablo compressors have now been listed by the same seller on eBay.

https://www.ebay.com/itm/254836260597?ViewItem=&item=254836260597

Of course, knowing what we now know (BTW our compressors are back up and running again as of today), you still have to ask yourself one question:

https://www.youtube.com/watch?v=A732Cuuo2tI