Need help w Hitachi Bebicon Air Compressor

[Barry Lawrensen]

I have a Hitachi Bebicon Air compressor, installed with black pipe to our school MakerSpace classroom.
Photo at: https://drive.google.com/open?id=1Pl...Ju3TLqLBwNCZEa

How do I adjust the standing pressure for the compressor? The installer set it rather high, based on the occasional use of power nailers. But normally, we only use the compressor for a laser cutter air assist, and HVLP paint sprayer.

I cannot find any user manual to help me know how to adjust the standing pressure. Can someone teach me how to adjust? Right now, the compressor runs to maintain about 130 PSI, but I think 50 to 80 PSI would be adequate, except for the occasional times when we need to use the air nailers.

I am from the USA, teaching at an international school in Hong Kong; thus the Asian compressor.

Thank you,
Barry

[Jim Becker]

For those branches that will be utilized for purposes that require a lower input pressure, you need to install (an) additional regulator(s). For example, in my shop, the port I use for HPVL spraying has a regulator just before the port that is set to 40 psi, which is the normal input pressure for my particular gun. My CNC machine's branch has a regulator that sets the input to 90 PSI as required by the manufacturer and another regulator on the machine that's set to about 35 psi for the Z-axis counterbalance. My main regulator at the compressor is set to 120 psi.

Using multiple regulators "downstream" from the primary allows you to tailor the pressure for individual uses without affecting other uses at the same time. You may also want to have additional filtration/moisture control for certain applications, too.

[Barry Lawrensen]

Thanks, Jim, that's a great tip!

At this point, I just want to turn down the main regulator at the compressor, and (ignorant question) don't know how to do that. There is a brass ring on the left side of the compressor, with a spring inside. Do I tighten or loosen to lower the pressure?

For those branches that will be utilized for purposes that require a lower input pressure, you need to install (an) additional regulator(s). For example, in my shop, the port I use for HPVL spraying has a regulator just before the port that is set to 40 psi, which is the normal input pressure for my particular gun. My CNC machine's branch has a regulator that sets the input to 90 PSI as required by the manufacturer and another regulator on the machine that's set to about 35 psi for the Z-axis counterbalance. My main regulator at the compressor is set to 120 psi.

Using multiple regulators "downstream" from the primary allows you to tailor the pressure for individual uses without affecting other uses at the same time. You may also want to have additional filtration/moisture control for certain applications, too.

[Jim Becker]

If the only regulator you have is "on" the compressor, that's not a great setup, IMHO. The one on the compressor is normally to limit the maximum for the compressor, itself. The one normally installed just off-board the compressor, usually with filtration, etc., governs the normal pressure for the "system". The additional units I mention are for convenience of function

I cannot help you with your specific machine relative to which direction to turn the knob. But your gage should tell you which way is decreasing pressure to the piping.

[David Bassett]

... There is a brass ring on the left side of the compressor, with a spring inside. Do I tighten or loosen to lower the pressure?

I'm far from a compressor expert, but the only thing close to that description on the little one I have is the safety valve. (Pull on the ring and it goes to 0 PSI (almost) explosively.) I think, especially in a school setting with its extra liability issues, you need to leave the compressor alone and just get regulators for your various tasks.

[Barry Lawrensen]

Yes, there is a wall-mounted regulator w water filter adjacent to the compressor. I'm disappointed in the installation by "professionals," who used clear plastic tubing to connect to the black pipe, which blew off the compressor barbed fitting after only six months of use. I replaced their tubing with a heavier, reinforced tubing and an additional hose clamp.

[Jim Becker]

Make your adjustment at the wall mounted regulator if you have one, not on any regulator that's physically on the compressor.

[Bill Dufour]

I do not think you have a regulator onboard. Above the pressure gauge you have an adjustable? pressure switch. you could open it up and reduce the set pressures so it will shut off at a lower pressure. Normally reducing the off pressure also reduces the on pressure.
To the left of the gauge, and up a bit, there is what looks like a emergency over pressure relief valve. Turnning that knurled ring may have changed the set pressure and it now may be too high. i would adjust it down until it blows off then increase pressure a little . Its job is to protect the tank from exploding.
To the left of the gauge is what looks like it could be a regulator or just a shut off valve.

I do not see any tube connecting the pop valve on the side of the regulator. This valve should release pressure between the tank and the compressor when ever the motor shuts off. That job may be taken over by the tube from the crankcase to the cylinder head. it may unload the valves when the crank is not turning?
Pipe should not be black iron, it will rust and rust will clog filters/regulators.
Bill D

[Tomac Carter]

Pipe should not be black iron, it will rust and rust will clog filters/regulators.
Bill D

What would you recommend?

[Barry Lawrensen]

Thanks, Bill, your detailed information is very helpful!

Maybe the pipe is galvanized, and not black pipe: it is painted, and I probably wrongly assumed that it was black pipe (like a natural gas line). Hong Kong is terribly humid, so the air does have a lot of moisture in it, which does get filtered out (to some extent?) in the wall-mounted water trap. But when I connect a blower nozzle, the air still has a lot of moisture in it.

After installation, a government-certified inspector was sent, who (via a translator from Chinese to English) told me that he must disconnect the compressor and used a USB borescope to inspect and photograph the inside of the tank to verify its quality. He said this type of inspection must be done every (5?) years, rather than annually if the borescope were not used.

[Barry Lawrensen]

Good advice, David.

I turned to this forum, because I am not experienced with compressors, and unfortunately the language barrier (and cultural differences) makes it difficult for me to find local advice here in Hong Kong. Not to mention, differences in safety regulations, which are all over the place here (from "safe" to "no apparent regard for safety"). The construction industry here still uses bamboo scaffolding, tied around buildings up to 40 stories high.

[Bill Dufour]

Interesting to hear they intend to open the inspection ports and actually inspect the inside of the tank. Good luck getting those plugs off. I had to use a 1" impact gun and a 1/2" hose. Turns out mine are parallel thread with a big O-ring. 2" water pipe thread I believe.
Copper pipe or pex is the recommended piping. Never PVC. I have heard that galvanized iron pipe is okay but it is only galvanized on the outside so I do not understand why it would be any better then black pipe?
Bill D.