Hatsun Lighting compressor help

https://www.amazon.com/Refrigeration-Technologies-RT201B-Gasket-Sealant/dp/B07C1V54SH



here’s that Nylog product I was talking about earlier. There’s a video of this product being used, to show its elasticity. A drop or so was stretched out to like 3’. It won’t harden up, fittings are easily removed years later, conditions your o rings, and I’ve never had a leak when I’ve used this stuff, ever. On a 3/4” pipe thread fitting, I only apply a tiny drop and spread it over the Teflon threads, so a very thin coat is all that’s needed. I’ve used it on all pcp fittings I’ve made up, like 90 degree fittings with a female foster QD on one end and a male foster QD on the other. No leaks.

I will try to take the pictures when I get another chance to work on it. I have it apart so that should be easy. I can tell you that it has 4 rings on the piston rod and they are not continuous. The have a split in them. I looked them over really good to see if they were worn. At first I though it was broken then I got out the replacement ones and realized how they went together. This is my first time working on a piston so I have no real reference but I haven’t seen anything like these. I’ll take some pictures of the replacement seals and those on the rod as well as the valve head and post them tomorrow.

Thanks for the help and input.

Thanks for the link on the Nylog product. I will add it to my next amazon order. 

....it has 4 rings on the piston rod and they are not continuous. The have a split in them....

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This is the Tuxing style rings. They can be installed much more easily but having a split may compromise the sealing ability to some extend so they use 4 rings. This reason is just my guess though. The other style is Yong Heng rings which is a continuous ring. Only three are used on the 2nd stage piston.

Now for something that is probably just a problem looking for a home. Seems from reading this thread that the Lightning uses the Tuxing style split rings, 4 per piston. I wonder if the YH style continuous rings would work with that piston/cylinder. If so, you would have continuous rings and one more as well beyond the YH design. Might work well. Might cause a problem.

Okay, here are the promised pictures. I’ll post them first. Then I need some input. Below are the replacement piston seals that were included in the rebuild kit sent with the Lightning compressor. Then a picture of the existing seals on the piston. Also, take note of the one picture of the piston rod itself. Not sure if this is a problem, but doesn’t look right. The piston is scarred up, it is below the seals but it is rough.



Now for the problem. So I redid the head and put the replacement gasket on and the O-rings as before. I started the compressor and it was building pressure really well, then stopped increasing around 3000 psi. Run a long time without increasing so I shut it down, kept the pressure in the system and checked for leaks again. I found a small one and thought now I got it. Started to fill my bottle and it was working fine but stopped building pressure again at 4000 psi. I shut it down again and went over everything one more time. Found a very small leak on the bottle gage. Honestly, I had not checked it before. Was checking everything without the bottle I was trying to fill. Anyway, 1st question, couldn’t get it to stop leaking so I took it about. I realized then that they had used some kind of sealant on the threads. I don’t know what they used and didn’t have anything but teflon tape. So I used it, knowing I saw somewhere that you shouldn’t. My question is why no teflon tape? I figured it was only temporary so I would see if it helped and it did the leak stopped.

So I tried to fill the bottle the rest of the way to 4500. However, this time it stopped at 2000 psi and would go higher and then I noticed that the pressure was back in the coolant reservoir. So I tore it down again and found this



The new gasket I had just put in was already chewed up. It hadn’t been in use for an hour. The original gasket lasted just over a year (but really about 7 hours). This one didn’t make it an hour. So now I am stumped. Either the gasket is complete garbage (but why was the first one able to last so long) or something has changed and the gasket is being damaged by the action of the piston. I did notice this part was just sitting on the end of the piston rod



I don’t know if maybe it is moving around and damaging the o-ring (maybe the o-rings don’t fit properly, but seemed to be right when I installed it) But the 0-ring was damaged to the point that air pressure was escaping into the coolant as described before. Below is another picture of the damaged 0-ring and the last of the repair kit replacements. The second (one on top of the other) is an attempt to show how much it has been stretched.



Thought I would go to hardware store tomorrow and find a different 0-ring to try, then I could find some where online to buy replacements. Where do you all recommend getting the replacements. If the original green ones are junk that may fix it, but if there is something else causing the damage, I’m not going to get far without replacing these things “often”. I think someone recommended a specific type of o-ring, that may help. I thought I would try one from the hardware store, that should let me know at least if the green ones are just no good. I didn’t take the head clear off because I didn’t want to damage the gasket. Anyway, I’m looking for suggestions.

I’m not sure when I will get back to this, maybe tomorrow morning but I will have to leave town later in the day and wont get back to it until later in the week, maybe Wednesday.

Thanks

Frustrated rgwv

Scratches on the piston – that should not cause any problems because that surface is not in contact with the cylinder wall although I would suggest you to file off those dangling burrs which may come off and do damage later.

Sealing threads – use Loctite thread sealants which are specifically designed to do the job. I use Loctite 542. The bad thing is that you will have to heat up the thread with a torch to soften the cured sealant when you want to loosen it in the future. Telfon tapes are good for tapered threads only. It’s mainly a lubricant for preventing binding, not a sealant.

Chewed-up O ring – It’s likely that the O ring was not seated properly when the cylinder is inserted into the head. The piston is only rubbing against the cylinder wall, not that O ring so it could not have been caused by the action of the piston. Make sure that the O ring is thoroughly lubed with silicon grease and all metal edges that will slide over the O ring during installation are deburred. That said, the quality of those green O rings from China are not very good. Get some quality ones from your local stores. Make sure that you get FFKM or Viton type which can stand the high temperature here. You may want to try different hardness as well. The more common black O rings ( Buna type ) are not usable.

It looks like there is going to be quite a bit of difference in the Hatsan and the AV. Totally different design. In the second picture you'll notice the two holes in the top of the large piston. This is a straight shot into the crank case so if the high pressure seals fail and you start compressing some oil that sloshes upward you'll start getting dark crank case oil and you'll also start seeing contaminated oil/water (black crap) in the onboard filter.

Jking 

It looks like there is going to be quite a bit of difference in the Hatsan and the AV. Totally different design. In the second picture you'll notice the two holes in the top of the large piston. This is a straight shot into the crank case so if the high pressure seals fail and you start compressing some oil that sloshes upward you'll start getting dark crank case oil and you'll also start seeing contaminated oil/water (black crap) in the onboard filter.

Jking

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Maybe I'm totally wrong but how could the low pressure piston have holes that go completely through "into the crankcase" and still make any pressure?

No, not the (first stage) low pressure piston the big piston that the small high pressure piston is mounted to, as in your second picture. Basically the the "large" piston in the 2nd stage is just a mount for the smaller 2nd stage high pressure piston. Kinda like this AV piston, notice the four holes in the top of the larger piston with the smaller high pressure piston mounted on top. These four holes in mine are open to the crankcase.



Even though this larger piston on the second stage has rings they aren't compressing anything, just helping keep it straight and snug in the cylinder I guess.

jk

Hey all,

I took a couple pics today that may help with the last few questions/comments regarding the comparison between the AV and Hatsan Lightning compressors. I just was putting things back together and thought I would show some pics, they may be helpful to someone. Things still aren’t working correctly, but first here are the pics:



Then this goes on top of the piston:



After getting things back together, I really thought I had it this time. I have checked and double checked for leaks and cannot find any in the external air line from the compressor all the way to the bottle. I first used the line plug and did a test to fill the line of the compressor to 3000 psi. It fills, but seems to take longer than it should. It goes fairly quickly until it approaches the set maximum fill pressure then it seems to just bog down and takes a long time to finish. Checked for leaks again while pressurized to 3000 psi and didn’t find any. It’s not much volume so it should fill relatively quickly it takes several long minutes. I thought maybe I’m just miss judging things. So I tried to fill my bottle to 4495 psi, which was already at 3900 psi it never got there. Just trying to fill the lines from the compressor to the bottle just to build the pressure(before opening the bottle), so roughly twice the distance length of the fill hose took me almost to the first auto purge, again relatively quickly to the 3700 psi mark, then very slowly forward. After two times of the auto purge (set at 9 minutes) it still had not went past the 3900 mark. After 27 minutes, I still had not moved past the 3900 psi. I just shut it off there and quit for the day. 

First question, is there something else internal that could cause this issue? I’m not sure where to start, but there are a number of springs an other o-rings and parts I assume are internal workings, that could cause the problem. I don’t have a parts diagram and Hatsan says they don’t have one so I’m not sure what all the parts are for without just taking the thing apart. The air leak into the coolant seems to be fixed for the moment. The valve stem seals didn’t look bad (see past pictures), but could they be worn. I would assume that even a slight wearing away of the thickness of these seals could cause the compression to drop off which I would think would impact fill times and maximum fill pressure. It just seems that whatever I have the pressure set to, it gets close relatively quickly, then doesn’t make progress. Is there a pressure switch or regulator that could be not working properly?

One other basic question, when you use Lock-tite on the pressure fittings, how much should one use? It looked like there was just a little of whatever they used at the factory on a few threads. I want to seal them, but will also want to get them apart if needed.

Anyway, thanks for any thoughts you might have on what I could be missing. I really wanted to stick the whole thing in the pond to see if there were any bubbles that showed up, but give what I paid for the thing, I thought maybe I better wait on the pond idea.

Thanks again,

rgwv

If you are sure that there is not any external leakage, then it has got to be internal. While there are a number of possibilities, I would suggest you to check the valves inside the 2nd-stage cylinder head. On Yong Heng or AV, there is a pair of reed valves with one visible right after the cylinder head is taken out and the other one buried inside the head. On Hatsun it seems that all valves are fully buried inside. There should be ways to take apart the cylinder head further to gain access to those valves. I found the way for my Yong Heng by accident.

When the 2nd stage piston goes down, the air passage going to the outlet is closed while that coming from the 1st stage output is opened. This allows compressed air from the 1st stage to be sucked into the 2nd stage cylinder.

When the piston goes up, the positions of the valves are reversed allowing high pressure air to go to the outlet but not back into the 1st stage.





For Yong Heng, there has been reports that dirt / carbon build up at these valves blades have caused pressure build up failure because high pressure air leaks back to the 1st stage. On your Hatsun, it can be a pair of check valves and the O rings have gone bad.

Hope it helps and good luck.

Okay guys, I'm back to trying to fix my hatsan compressor. Taking the second cylinder head off.




How do I remove this head. It appears to be in two parts the main body and a "lid" which is about 1/4 inch thick and appears to be sealed with something. I have tried using hand pressure, no way, I'm afraid to pry with anything, the aluminum is so soft. How to I get it apart with ruining it? Also what do I use to seal it back. Looks like some kind of yellowish (almost clear) ruberish gasket material.


I'm trying to get inside to see the check valves and whatever else is in there that could prevent a pressure build up. 


BTW, was able to order a rebuild kit from Hatsan for 35 including shipping. Which is a lot given the orings aren't good. So I basically paid for the gaskets and springs and such.


Any suggestions would help at this point.

I would call this the low pressure side and the first cylinder. I've actually dug into this one. Yes they are on tight the gaskets seem to stick down really well. You will ruin one taking it off. A sharp blow from a rubber mallet will separate it or very gently pop it up with a coated screw driver between the green gaskets.

Now for the pain. It that 1/4 inch plate comes loose whoa. This plate allows to access to the water jacket that cools head. As far as sealant. It must be Smurf snot. I tired regular blue gasket sealant it leaked. Finally purchased some Flex seal and kept it from leaking.

Now for the "what" comment. How did you get Hastan to sell you a rebuild kit??? I asked them on multiple occasions via email and they would never give me an answer. I'd like to have a complete set of seals/gaskets in my possession just in case something like this happens.

If your purpose is just to examine the check valve, there is a good chance that the valve is behind this fitting. Suggest you to remove this fitting and check before attempting other more challenging things.

Not sure on the Hatsan but on the AV there is a check valve on the high pressure side where the cooling coil tubing screws into the water separator. You might have one in a similar position.

jk

Just curious on the o ring types for resealing/rebuilding a HPA compressor. If one were to source all the o rings required what would be the best type? Viton? Buna? PTFE? Also, what durometer grade, 70 or 90? I think while I have the hatsan o ring kit still on hand, I’d like to build up another set or two, maybe go up in grade.



Thanks in advance, all. To the OP, I hope you get it all fixed up.

Just a follow up with a photo from my comment above. This again is a AV so it might help others with AV's and maybe even the Hatsan owners. This is where the high pressure check is on the AV.