Yong Heng Compressor Review+Setup

So I bought this compressor out of a necessity of having 3 air tanks and paying 5$ per fill at the scuba shop, only to get it filled to about 4000 PSI. Yong Heng Compressor was a great alternative since I could get a water-cooled compressor with automatic shut off for 300$. Note: Only the 220V Model has automatic shutoff. The 110V doesn't have Automatic shutoff but it allows you to continue filling past 4250 which is a good thing in my opinion.
So I think they raised the price about 20$. It's 204$ for the compressor and basically another 100$ for shipping. Wouldn't it be amazing if the compressor was here in the United States? 200$ for a hit/miss compressor is a good deal in my opinion. Hit or miss because of something I ran into which is likely that future buyers will too. I will get into this later.

It comes in a full-size China Crate. Very good styrofoam and good packaging. Sadly mine did not come with any instructions. So i had to look up youtube videos and the instruction manual online: 
https://www.casogo.com/Manual/qibang_30Mpa.pdf
and Youtube videos like this one:

And this one


My first impressions were very good. It is very portable with a handle! It also is extremely tiny and has less length than a ordinary typewriter. 
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Here is it compared to sunglasses and all the items that come with it. 
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Now setting it up was somewhat self explanatory after watching the vids. Water intake starts at the bottom of the piston(air piston) and brings water to the top(heat rises) and back into the bucket you will need to provide to cool the unit. 
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Then you will need to provide your own source of oil to lubricate the unit. I was lazy and got 10w/30 Mobile One synthetic i use for my 1990 Volvo Turbo Wagon :). I think they suggest hydraulic oil in the instruction manual which i will switch asap as the oil is already turning black. 
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I ordered the 220V version which included the automatic shut off. Not necessarily a good thing since I will now reveal that my gauge is off 400 Psi! Meaning it auto shutsoff at around 3750PSI instead of 4500 or 4250. This is very annoying and I will work on trying to get around it. I also had to do a ton of rewiring from my Air condition plug(I live at a hotel). Wiring was strange since it used the 2 plug pin for 110 devices like iPhone chargers and fans. I had to splice the wires and make custom pins, and new specialized 220v plug sockets that i got from my local electric store. I'd much prefer the a/c plug that comes in the European versions of the compressor. I tried plugging it into the 110V sockets as I was in disbelief that even the tiny water pump took 220V but it was true! 110V sockets just did not cut it, the pump was barely pushing any water. So i had to do some improvising shown here. Get the 110 Version if you want simplicity that is for sure hahah. 
Before:
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After

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Stock Plug

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New Plug

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Performance:

It fills fast, there is no doubt haha. Filled my tiny paintball tank in like a minute or two. Using semi-icy water I obtained temperatures just below 50 degrees celcius. I believe max temperature that you don't want to pass is 65 degrees(found on another thread on here). Even with big tanks I filled a 75 CUFT 4500 Air venturi from 0- 4500 in around 30-45 minutes(with two breaks, I think). 

Cons:
There are some obvious cons with buying a Chinese 200$ Air Compressor. One is that the gauge was so far off so my compressor kept autoshutting off at 3750 PSI instead of 4250 as i would have liked. Only have used it a few times so I will keep you guys updated on that. 

Secondly: There is no desiccant or moisture trap. I suggest if you live in humid climates or spilled a bucket of water in your room like I did, to turn on the aircondition and make sure the intake air is dry. 

Thirdly: Strange burning smell. Seems normal but smells funny when using it. I guess i need to change the oil asap.

Fourthly: Loud as an air compressor for nail guns. Its to be expected though. Not too bad when you close the door behind you.

Fifth: 220V version comes with strange plugs and autoshutoff feature is only good if your gauge is accurate. Mine was not.

Pros:
As someone who used to fill via Hill Pump(waay back in the day) mk 4 on my wildcat and then upgrading to CF tanks that I had to get filled at the scuba shop for 5$ each, I am greatly satisfied(need more time to tell actually) with the fact that I will pay off the Compressor in 60 Fills! 300$/5$(scuba shop price)=60 fills needed. 
It does have its quirks but the quality is actually not bad. They did not make this thing out of plastic surprisingly and they are using a very efficient water cooling method that some 2000$ compressors don't even have( I think some are air cooled). It fills fast. Its simple to setup. So basically, I don't really see why one shouldn't take the dive on giving this compressor a try. I suggest getting the 110V version if you don't want to chance your gauge being off like mine. You will have to watch it fill but I just don't have the guts to walk away from a machine compressing 4500lbs of air. Then again I wouldn't want to be too close to it either.

Score: I'd give it around a 7.5 out of 10. 

 
"douger"looks good I had a omega but only fill 1 bottle traded it but think ill be buying the 110 version
Yeah just tried filling it again. It only fills to 3750 PSI :(. I guess ill contact the manufacturer. I heard China has surprisingly good customer service. Lets see what they can do. Man, what is up with my luck in receiving defective products? I've received DJI googles(virtual reality headset for drone camera) from ebay with dead pixels, a defective FX Impact, and now a defective compressor smh.
 
I figured out how to wire mine so it bypasses the auto-matic shut-off, It's very simple and I would highly recommend just buying the 120v model, it's only 40 bucks more and has so much less electronics, relays and bad shut-offs.

It pumps so crazy fast you can just sit and wait every month. It only takes 20 minutes to top off a 4500 psi tank from 3000 to 4500. 

Otherwise really really great compressor for the money. 
 
"MoeHofer"I figured out how to wire mine so it bypasses the auto-matic shut-off, It's very simple and I would highly recommend just buying the 120v model, it's only 40 bucks more and has so much less electronics, relays and bad shut-offs.

It pumps so crazy fast you can just sit and wait every month. It only takes 20 minutes to top off a 4500 psi tank from 3000 to 4500. 

Otherwise really really great compressor for the money.
Do you mean the 220 model? How did you bypass auto shutoff?
 
It's very easy. take the two wires running to the motor and wire them to the other side of the main switch, This bypasses the relay, the auto- shuttoff and all that other junk.

I wish I knew how to post pics, then I could send you puctures.

I like to fill my tanks to 4700 psi anyways. That way when they cool off they are right at 4500.

If you would send me an email, or a phone number I can send you pics from my phone, sorry I haven't taken the time to learn how to post pics

 
"MoeHofer"It's very easy. take the two wires running to the motor and wire them to the other side of the main switch, This bypasses the relay, the auto- shuttoff and all that other junk.

I wish I knew how to post pics, then I could send you puctures.

I like to fill my tanks to 4700 psi anyways. That way when they cool off they are right at 4500.

If you would send me an email, or a phone number I can send you pics from my phone, sorry I haven't taken the time to learn how to post pics

Interesting! Thanks! I could teach you how to post pics. I'll send you a pm.
 
I HAVE HAD A CHINESE 4500 # COMPRESSOR FOR 9 MONTHS AND I AM VERY HAPPY WITH IT. I PUMP TO 3200# FROM 0# IN ABOUT 4 MIN. 1800# TO 3200# IN 2.5 MIN. THE ONLY PROBLEM I HAD WAS SEALING MY HOSE FROM LEAKING. I FINALLY USED "J.B. WELD" AND NO MORE LEAKS. MY PUMP IS THE ONE THAT HAS A GOLD COLOR TOP CHAMBER AND WATCHING YOU TUBE IS VERY EAY TO REBUILD. I PAID $210 PLUS $135 SHIPPING. I ORDERED ONE FOR A FRIEND AND HE LOVES IT. IT SURE TAKES THE WORK OUT OF PUMPING.
 
"KROD"I HAVE HAD A CHINESE 4500 # COMPRESSOR FOR 9 MONTHS AND I AM VERY HAPPY WITH IT. I PUMP TO 3200# FROM 0# IN ABOUT 4 MIN. 1800# TO 3200# IN 2.5 MIN. THE ONLY PROBLEM I HAD WAS SEALING MY HOSE FROM LEAKING. I FINALLY USED "J.B. WELD" AND NO MORE LEAKS. MY PUMP IS THE ONE THAT HAS A GOLD COLOR TOP CHAMBER AND WATCHING YOU TUBE IS VERY EAY TO REBUILD. I PAID $210 PLUS $135 SHIPPING. I ORDERED ONE FOR A FRIEND AND HE LOVES IT. IT SURE TAKES THE WORK OUT OF PUMPING.
Please locate your "Caps lock" key and use it haha.
 
I was just wondering about the temperature of the stainless pipe off the HP head myself. Like Hajimoto above, I noticed that within seconds (maybe 15), the stainless tubes get too hot to touch. The temperature gauge on the water block basically still reads room temperature. It seems to run fine, but those stainless tubes are probably up over 200F.

I think it makes sense that they get extremely hot - the pressure compression is around 200:1 (going from 15psi to 3000psi) and the volume compression is, let's guess, 10-20:1 (assuming a 2" piston with a 2" stroke in the 1st stage, which is roughly 100cc, and 5-10cc of volume in the output tubes and microbore hose with a cap on it). Given those parameters, it seems reasonable that the stainless output tubes would be way too hot to touch.

304 Stainless tubing (which is what I assume these are made of) has a derating factor when used at high temperature and high pressure. I am going to try and put a thermocouple onto the tubing to see how hot it gets. The derating factor is only 6% at 400F but it goes up to about 25% at 750F. Without some data it's a bit hard to say whether this is an issue in and of itself - and potentially another concern is the thermal cycling of those output tubes. Lots of people use their Yong Heng to do 30-45sec refills directly, so 100s or even 1000s of thermal cycles can happen in a year. But really, I need to mount some sort of temperature sensor to the tube itself and see how hot it gets and how quickly. My guess right now is that the tubes don't ever get hot enough to worry about thermal cycling issues. I'll try and see about getting some temperature vs time data on the output tube this weekend.
 
With 30+ years in the compressor industry, 55C [131 F] isn't out of the norm for that kind of pressure, we see 200-300F discharge temps on recip types like you see in the local tire shops, screw types run at 200+F , oil free screws run up to 450F, these are all at 125-175 psi. 5000 psi 100hp units are typically 4 stage or more units, not 2 like you see in these small hp units. Compressing air produces heat and condensate, both enemies of the end application. I am amazed at the paintball places that allow you to 'plug in your tank' with out any regard for the customers safety, in the industrial world there are safety measures in place like placing a SCBA tank in a cage while it fills....I don't see anyone as an authorized repair center for YH compressors, who is ?
 
My compressor regularly gets up over 60c. I just changed the digital gauge from c to f so I'll need to monitor to see if that makes a difference. (Not sure if the YH digital gauge was accurate?)
Also I discovered that the YH moisture bleeder needs to be set up correctly. The bleed screw/manifold should be the lowest point in your filling set up.
From the Aluminum manifold make sure all you set up is above that point. Don't allow the line to sag or the bottle being filled to be bellow that point. The moisture tends to pool in the lines and not get bled off.

 
I just fired up the new YH for the first time today. $220 on eBay. It was ordered on Sunday and arrived on Tuesday. The battery needed is a 357. It filled an empty Marauder very quickly and the noise wasn't as bad as I thought it could be. No Chinese smells at all. This one is, I believe, the hard case model. My gut feeling is that they may have had some manufacturing issues early in production but they got better. The inline filter obstructed foster connections and it was necessary to add an extension line on the exit side of the filter. A more advanced oil air separator will be added. All in all, this is a very impressive compressor. It's hard to justify six times the cost to go to the next level.
 
You ordered the 220V version which included the automatic shut off. Your gauge was off 400 Psi Did you ever figure out how to fix the compressor so it did not shut off early, I am having the same issue.

If you want to disable the auto shutoff, Just disconnect the wire from the manometer. It's as simple as that. It is possible to replace the gauge with the adjustable shutoff unit, without any wiring modifications. Just plug the new gauge into the same plug as the original one was connected to. I prefer to have no auto shutoff and turn the thing off when I want it to stop so that I can purge the pressure as in the instructions.