Hydraulics International issue

[broncobowsher]

Friend has a 3G-SS-20-O for some rebreather cylinders. He dropped it off and I agreed to look at it while he is out of the country. Hooked up some hoses and pressure gauges fired it up. When he said it was broke I didn't ask many questions as I figured it would be easy enough to figure out what was broke. Well I was wrong. It does pump. 750-1000 in and get 1500-2000 out. I have it just pumping air in the hoses and the low side drops and the high side rises. It works.

But I think there are other issues. It wants to cycle very fast. My reference is the Haskel I own. Each cycle on the Haskel is fairly slow and deliberate. But not on this HI booster. The compression cycle is throttleable, but the return stroke is fast, very fast. I feel like the return stroke needs to be throttled back a little. This is what I am thinking "it's broke" is about. Trying to find video of the booster running on YouTube shows the HI runs about the same as my Haskel. There is a plastic filter with a mesh screen on the HI for the discharge muffler, doesn't have the speed screw that the Haskel has. The only throttle is a ball valve on the drive gas.

So while I am waiting a response from the owner/friend of this booster I figured I would ask if anyone has some knowedge of the booster and what to look at. Any links to diagrams or service manuals would be great as well. I don't want to cause more damage for no good reason. I think the issue is in the control circuit as the pump appears to actually work.

Hints, directions, suggestions (besides replace it)?

 

[Mendigo Diver]

HI boosters are louder than Haskels and the return stroke on these small single action ones is fairly loud and far faster than the Haskels. Sounds like it is operating normally to me. Personally I prefer the HI, seem to use less drive gas and be better made (more durable).
I see another post here asking about parts for HI pumps, same response, contact HI for parts and schematics, I have found them helpful previously (I have a 3g-ss-20)

 

[Wookie]

HI boosters are louder than Haskels and the return stroke on these small single action ones is fairly loud and far faster than the Haskels. Sounds like it is operating normally to me. Personally I prefer the HI, seem to use less drive gas and be better made (more durable).
I see another post here asking about parts for HI pumps, same response, contact HI for parts and schematics, I have found them helpful previously (I have a 3g-ss-20)

I also have one, and find the return stroke to be quite fast when compared to my Haskel boosters.

 

[broncobowsher]

I'll try and get a little video in the next couple of days. Maybe it is working fine?

 

[rjack321]

does it get to 3000psi with 1000psi source and 150psi drive?

The only throttle is on the drive gas
and the 2 strokes are not symmetrical either

The shuttle spool is behind the muffler and comes out after removing a couple screws and an aluminum barrel. That can sometimes get sticky and need cleaning and lubing. <10mins

The drive gas piston Oring can get worn and if it gets bad bad it will score the inside of the drive piston which is fiberglass. ~20-25mins to disassemble the drive section, check, lube, and reassemble

The check valves are primitive and require a special 2 prong tool to remove - along with a prayer they aren't seized. They wear out fairly fast and leak, negating your boosting.

the O2 side is user serviceable, I have done mine once. The parts kits are pricey and if you need something extra like a new drive barrel HI has a minimum order of like $250 or something so unless you order the service kit after you disassemble and check for other wear or breakage you get in a bind.