How I adjust scuba gear

Maintenance scuba gear is very important, but adjusting it even more.

A regulator set what had maintenance but isn’t adjusted right doesn’t breath well. It can give too much air, what isn’t always too bad, but can also give too less air, what gives stress and can become very dangerous.

That’s why it’s so important to adjust the regulator set to it’s optimum performance.

It’s very important we do that with the right knowledge, tools and measuring equipment.

This is the tool I use to adjust the second stage:

This can be placed in between the hose from the first stage to the second stage,

Like this:

Of course the middle pressure has to be set to ideal first. Most of the time in between 9,5bar/135psi and 10bar/143psi, but always check the manufacturer’s guidelines to make sure. To see if that’s the case all the time during adjusting the second stage it’s good to have a middle pressure meter on the second stage adjusting tool.

The outside of the tool, the black handle and the 2 ends, with the pressure gauge on one side, are static. The middle part, with the wheel on it turns, to adjust the poppet in the second stage.

When the second stage with het adjusting tool on it is still leaking a little bit the middle pressure meter on that tool will give a lower measurements than the other meter. That’s how you know the second stage will or will not lose air. Even if you can’t hear it anymore.

This can also be done with a simpler device, like this one:

The problem with the simpler devices is they only are made for 1 purpose and 1 kind of poppet and they don’t have a dedicated middle pressure meter.

Because of that and there are roughly 2 kinds of poppets I prefer the one with the middle pressure meter and what can be turned around.

These are roughly the 2 kinds of poppets in second stages (some brands still use their own kind of fitting):

As you can see, you can’t adjust them with the same tool, because the fittings are different.

The adjusting tool I use has one fitting on one end and the other on the other end. I only have to take the middle pressure meter of and put it on the other end.

As we have set up the adjusting tool like we did in the picture above, the one with the second stage on it, with air pressure on, we turn the wheel on the adjusting tool to the left until the second stage starts blowing out air. Than slowly turn it right till the airflow stops. Than again turn it a little to the left to make sure the second stage starts blowing air as soon as we turn it just a very tiny little bit and turn it the same tiny little bit to the right to close the second stage again.

After we did that we go breath a few times trough the second stage and press the purge button, to see if that all works well. After that little test we turn the wheel on the adjusting tool a little left again to see if it still starts blowing as soon as we turn that wheel. Of course we also turn it right again to just close the second stage again. Never turn it further than absolutely necessary.

Now the second stage should be adjusted perfectly.

To be sure if that’s the case, we will use a manometer what can detect the difference between the in and out going port. Also called a magnehelic meter.

I use this digital manometer for that.

Yes, the black pipe is a hose protector. I drilled a little hole in it, so the little hose just fits in. That’s not as perfect as a professional pipe, but good enough to see if the second stage is breathing as easy as it should do.

This hose protector just fits in the mouthpiece and with a little bit of pressure it will seal completely.

The difference between breathing through the tube with and without the second stage on it must be as low as possible. I prefer les than 0.2kPa / 0.03psi.

Of course we can also do this process by trial and error. Take the hose of the second stage, turn the poppet, put the hose back on and set pressure on it to see and hear what it does and keep on doing so till the second stage doesn’t blow air anymore, but that’s never as accurate as with an adjusting tool and a manometer. And it will cost us way more time to adjust our second stage.

We don’t need too much tools for maintaining our scuba gear, but we do need good and some dedicated tools.

Not having and using the right tools can work very frustrating and that’s a thing we don’t want and certainly don’t need. Servicing and adjusting our scuba gear must be done the same way as we want to dive, relaxing.

Make absolutely sure you know what you are doing before you go do this yourself. Maintaining and adjusting our scuba gear is of vital importance. Please leave it to the experts if you’re not the full 100% sure you do understand how to do this. Please don’t think you can teach yourself. That can be very dangerous.

Adjusting the middle pressure on a mares first stage is very easy. Those first stages have a big 10mm hex screw on top. In the ice regulators that’s under the blue membrane what holds the oil in.

Adjusting a Scubapro, Sherwood or similar regulator is more a trial and error process. They don’t have an adjusting screw. You have to put or take out washers under or above the spring what regulates the pressure on the valve. Most of the time 1 washer will make all the difference you need. Those washers aren’t as thick as normal washers from the construction market. They’re specially made for those regulators and you have to order them from a specialist store.

When you need more than 3 of those washers you better order an new spring, because the old one is worn out.



Back to topBack to home page