I recently bought a new Yong Heng. I was having trouble with my 5 year old one that I have since fixed. The new one seems to heat up very fast. Ran it for 10-15 minutes under no pressure. I then topped of my Benjamin bottle a couple of times. It was at .5 hours of run time so I changed the oil. I’m using Amsoil synthetic compressor oil. Yesterday I went to top off my 6.8l bottle and had some issues. I only needed to run it about 10 minutes. It heated up fast again. Went up to almost 70 C and right before I went to shut it down my breaker blew. I’m wondering if it just needs some more break in time or if it has an internal problem? When I first got the old one I didn’t own a bottle so it had some hours on it just filling guns.
- The AGN App is ready! Search "Airgun Nation" in your App store. To compliment this new tech we've assigned the "Threads" Feed & "Dark" Mode. To revert back click HERE.
New Yong Heng question
- Thread starter redtrucker61
- Start date
Doesn't sound good. In my opinion they should not be run anywhere near that hot. If it were me, I'd tear it down and inspect it. I assume you're getting decent water flow?
Upvote 0
Well one factor that is pretty Universal with electricity is if you have a circuit that is marginal it will drop the voltage and whatever you're running on it will pull more amps to make up for it to whatever wattage it needs this will heat things up but other than that 10 minutes pretty much will heat a compressor up put a fan on it
Upvote 0
Assure screen on back of water pump is fully open. Also, plenty of water, chill 
with ice bottles, pre-chill room temperature compressor to 18 degrees C before using. Run external fan behind compressor from beginning to completion, even to cooling down electrical motor after shut-down. WM
Upvote 0
I’m using the same circuit and water pump as the old unit. This new one is just not running like the old one did. I had filled my 6.8l bottle from empty doing 3 run and cool down periods with old one. I could run the old one for 10 to 20 minutes at a time for refills and it would never go above 60c. I’m just disappointed. The old one still fills my bottle fine. I just thought I would be good to go with a new unit. I’m going to do some more short runs at lower pressures with this new one. Hopefully it will break in.
Upvote 0
I always kept a couple half gallon milk bottles of water, (3/4 full for expansion) in my freezer to drop in water reservoir when running theYH. Also had 2 external fans, front & back blowing on compressor. NEVER overheated in 3.5 years. As Worried Man said, make sure you're getting full water flow through pump & hoses too.
Upvote 0
I fil my 45 minute SCBA tank about once a month with my 2+ year old YH and I never let it get to 70 C. Normally it doesn't go over 60 C. It will climb rapidly to around 50 C and then go up much more slowly from there. I don't use ice in the water in the winter (it is in a unconditioned room off my garage) but I have a small computer radiator on it and a fan on the motor. I can fill my tank from 3000psi to 300 bar in one run but normally I start at 3200 or 3300. I think my tank is similar in size to yours.
I'd at least check and possibly upgrade the cooling pump, they are cheap. The temperature gauges are also pretty cheap on these pumps and you might try swapping them with your other YH. If it is really getting that hot and it isn't because of poor flow I think the best you can hope for is it gets better with more use. Ice in the water and a fan on the motor will help.
I'd at least check and possibly upgrade the cooling pump, they are cheap. The temperature gauges are also pretty cheap on these pumps and you might try swapping them with your other YH. If it is really getting that hot and it isn't because of poor flow I think the best you can hope for is it gets better with more use. Ice in the water and a fan on the motor will help.
Upvote 0
At around 12 hours run time I replaced the high pressure rings on my Yong Heng (replaced low pressure and high pressure piston assembly with improved parts). After reassembly it was heating up quickly and running hotter than normal. I did lightly lube the cylinder walls during reassembly but I took it apart and put a heavier coat of compressor oil on. After a couple of runs to break it in and work any excess lube out of the top end it started to run at normal temperature again.
I also fill a 6.8L tank (usually from about 250 to 300bar). My run times average 10 to 12 min and temp stays under 122°F (I changed my temp gauge to Fahrenheit unit). I run mine with a small fan blowing on the unit from the back and a block of ice in 3 gallons of water.
I also fill a 6.8L tank (usually from about 250 to 300bar). My run times average 10 to 12 min and temp stays under 122°F (I changed my temp gauge to Fahrenheit unit). I run mine with a small fan blowing on the unit from the back and a block of ice in 3 gallons of water.
Upvote 0
If true, this would be the first time I'd heard of a Yong Heng running hot until broken in. Fortunate, you have an extra water pump and digital temperature display to switch out to narrow down problem. Five years with a Yong Heng, I'm sure you know what a normal cooling water flow looks like, check out new water pump rating, my three-year-old is 600L/H, some early ones were 400. Best of Luck, WM
Upvote 0
I’m still running the water pump from the old unit. I did check water flow. The water seems to be running through just as it did before. Due to work it will be a few days until I can play around with it again. I didn’t look at flow rating on the new water pump. I. Just put the new one in place of the old one. When I bought the older one I didn’t own a tank. For the first year or so I was just doing short runs filling guns to 3000. Since I wasn’t filling a tank until it was well broken in I didn’t know if this was normal on a new unit.
Upvote 0
Yong Hengs are heavily discussed, three years associated with this forum, never heard of high temps till broken in. If, after trying different water pump and digital temperature display, the problem persists, something in the high-pressure cylinder is generating temperatures far higher than normal. If so, should be covered under warranty. WM
Upvote 0
Why are you running it so long in the startups? I run my in the startup phase for maybe 3 minutes. I run a larger water pump using ice bottles in my distilled water. No external fans and going from 4200 psi to 4500 in 12 minutes. The temperature rarely gets over 58c .
No other drain on my 20 amp circuit during pumping. I also chill my air vessel for 15 minutes with ice water.
I did rebuild both of my HY , second stage piston fail. Not a big issue. Just make sure the flapper reeds are in correct orientation. Took some research, but the forum came through for me.
To much oil is as bad as to little.
Hope you find your cause of the heat.
Good luck.
Upvote 0
The very first time it ran I did the 10 to 15 minute break in under no pressure. Now I start it with both pressure releases open for a few seconds then close them and let it start to build pressure. I did reach out to seller yesterday for input. So far no reply. Not sure if I will get help on this. Bought it back in November, then had a medical issue and a pacemaker put in. . So I’m just now getting a chance to use it. I also had replaced the complete bottom and upper cylinder assembly on my old unit about 2 years ago. Since my old unit is still working fine now if I get no reply from seller I will just use the old one for time being. Then I may just replace the complete lower and upper cylinder assembly on the new unit.
Upvote 0
If little hope for warranty claim and ruling out water pump, digital temp display issues, I'd pull aluminum high-pressure top hat to investigate. Since digital display reads temps from top hat base, seems a logical place to start. Appreciate sharing updates, Best of Luck, WM
Upvote 0
No reply from seller yet. I checked water pump. I must have changed them and forgot. It’s the new pump in my 20 gallon water tote. It’s rated 600l/h. It’s flowing good. When cold there is less than a 1c difference between the 2 gauges. I emptied out my Benjamin tank just to try. I ran the new compressor tonight. It only took about 5 minutes to heat up to 60C before I shut it down. It took the benjamin tank from 0 to about 2400 psi in that time. Hopefully I will hear from the seller soon. I don’t want to be tearing into this.
Upvote 0
Agreed, something isn't right in high-pressure assembly, generating heat too fast, in the 3-4 minutes it takes to fill a gun, never even break out of 40's-degree C. Curious as to comparison of fill times to reach 2400 psi between both Yong Hengs, if new one isn't generating pressure like the first, another sign of high-pressure system problems. Good luck with seller, pulling tophat, as long as you're careful with SS lines, isn't that bad, might cost you a gasket but eBay has them. WM
Upvote 0
Is the water pump the OEM pump ?
I know from personal experience that in cooling systems, too high a flow rate does not allow the coolant to extract the heat from the desired area. There’s a limit how fast you can force water through. How that’s determined, I don’t know.
Upvote 0
Do some research on that, research IS NOT reading something on a forum someone said (That includes what I type here, do actual research), look at science and what racing applications are doing. There is no such thing as too much flow through a radiator. That myth has been repeated for decades, and the science and real world application in racing has always rejected it.
Upvote 0
OK. Remove the thermostat from your cars cooling system. Don’t go too far from home. Ask me how I know.
Upvote 0
I'd like to correct something I said on my former response.
I filled my 90 cu inch air tank to today and double checked the max temperature the YH reach while going from 4200psi to 4500psi. It ran for 20 minutes and reached 65 c.
I filled my 90 cu inch air tank to today and double checked the max temperature the YH reach while going from 4200psi to 4500psi. It ran for 20 minutes and reached 65 c.
Upvote 0