Regulator issues after servicing

[halocline]

I would make sure they check IP at full tank and near empty. It's very easy, just start with a full tank, check, close the tank valve, bump the purge lightly until the SPG is down to 300-500, check again. It should be the same.

But personally I might be tempted to have someone different check it. It probably doesn't matter.

 

[arcie]

I would make sure they check IP at full tank and near empty. It's very easy, just start with a full tank, check, close the tank valve, bump the purge lightly until the SPG is down to 300-500, check again. It should be the same.

But personally I might be tempted to have someone different check it. It probably doesn't matter.

Thanks, I will do this!

The Mikron second stage can be adjusted with a flat head screw driver. Likely the shop adjusted it to the new seat but use changed it just enough to create the hiss. Should be an easy fix. Curious if closing the adjustment knob stopped the hiss.

Unless you saw a bubble leak you were not losing air while diving.

Thanks, yes, closing the adjustment knob did stop the hiss. No bubble leaks that I saw and buddy/spouse said he didn’t see anything coming from my 1st stage.

Several times I fixed an hissing reg while already on the boat and discovering the problem during pre-dive checkout...

I didn’t hear anything prior to the dives, but pre-dive check time was very limited, loud, and rushed. So not sure on this, I could have missed hearing it in the commotion.

One other thing I forgot, (Couv would have thought of this, RIP) since the Mikron is a diaphragm 1st stage, if there is an issue with the balancing, then IP would be higher at lower tank pressures. That could explain both the free flow at the end of dives, and could contribute to the higher WOB at depth IF you are following the typical Cozumel dive profile where you descend quickly to the deepest part of the dive and then make your way up slowly. In this case, the depth is irrelevant, its the higher tank pressure that is causing higher WOB because IP is lower. You can have a competent tech check IP at both 3000 and 500 PSI and compare them. They should be about the same.

I will definitely ask for this, thank you!

Did I misread something? I understood that the hissing was noticed toward the end of a series of dives, not at the end of each dive? Could the OP clarify?

When you go in, ask them to test the gear BEFORE they service it again.

I started hearing it after a few days of diving, at the end of the dive while waiting for the boat. My habit is to turn the adjustment knob off after I’ve surfaced and buddy and I are okay, to avoid free-flows, save air in case of any mishap etc. The surface was a little choppier a few days in and I was tired, so I decided to turn it back on and use the reg while waiting for pickup. That was the first time I heard it (last dive of that day). First dive next day, I checked that again on the surface and the same thing happened, at which point I stopped using the reg, switched to the shop’s.

And thanks, yes, will ask them to test it with me there!

1) what was the first stage intermediate pressure?
2) did it drift and lock up at a higher pressure?
3) did it continue to creep?
4) what was the second stage cracking effort

And before you take it in...
does the lever rattle when you shake the second stage unpressurized? You can probably see the lever thru the mouthpiece up against the diaphragm. Is it loose when you hold it over your head and look up, and then turn the reg over?

Yeah, your questions will perhaps upset them.
But then, I think they might deserve it.

I’ll check that out and let you know, thanks!!

And again, thanks to all. I really appreciate your time and advice!

 

[rsingler]

Since the adjustment knob appeared to solve the problem, we may have created a tempest in a teapot with our discussion here.
It may be that everything is just fine, and your shop did a great job, handing you a reg tuned very light (just like a lot of us like it). After a few days diving, plus the reg sitting each night with pressure off, the poppet spring may have just indented the seat (as it always does). With your reg tuned light, that might have been enough to allow a slight freeflow, which you fixed with the knob.
If all this is the case, you may have a perfect reg set, which just needs a hair of a re-tune now that the seat has "taken a set". We may have jumped on the shop a little too hard. (Or not.)

As a small point, always store your reg unpressurized reg with the adjustment knob out all the way. Turning it in increases poppet spring pressure, and increases seat indentation.

Hope it all turns out for the best!

 

[BoltSnap]

We may have jumped on the shop a little too hard.

As typically happens here on SB without having all the facts in and understanding the full picture and story.

 

[The Chairman]

Do your SAD kit include an inline adjustment tool of a bi-orientation (both flat blade and hex)? My SAD kit may have to get just a little bit bigger. (it does include a smallish IP gauge-and a adapter for the honking SP Air2 hose QD fitting...)

It used to, but it's more gimmick than anything. I carry a small IP gauge and the appropriate hex wrench to adjust my second stage. I borrow a bucket for use as a magnahelic and I'm gold.

 

[OrcaTorch's Amazon Dealer]

It used to, but it's more gimmick than anything. I carry a small IP gauge and the appropriate hex wrench to adjust my second stage. I borrow a bucket for use as a magnahelic and I'm gold.

Hi, I sent you a message.

 

[uncfnp]

@arcie I am absolutely not suggesting you do this with your regulator. But you might want to watch this video to see what a few of us think could be the problem with your regulator and help you understand how it all works.

In the video he is adjusting the cracking pressure on the second stage from the hose end. It is the procedure we were discussing earlier that can be done with a flathead screwdriver on a Mikron. You will see this done in the video. When a new seat is installed this setting can change with use and if set close to the edge of freeflow it may cross into actual freeflow. This is what @rsingler was describing in post #33.

And this is why I asked if turning the knob stopped the problem since in essence that knob “detunes” the regular, making it harder to breathe but also mimics what would happed if the regulator was tuned as shown in the video.

So in short, I think your regulator may simply be tuned a bit too hot now after use and a simple adjustment (shown in the video) will bring it back in tune.

 

[rsingler]

Can't wait for the verdict!

 

[davehicks]

It used to, but it's more gimmick than anything. I carry a small IP gauge and the appropriate hex wrench to adjust my second stage. I borrow a bucket for use as a magnahelic and I'm gold.

I just 3d printed a little 2nd stage adjustment screwdriver for my Save a dive kit. Inline adjustment tools are overkill imho, and a 3 inch plastic screwdriver modeled on an inline adjuster hits the sweet spot.

 

[Angelo Farina]

@arcie I am absolutely not suggesting you do this with your regulator. But you might want to watch this video to see what a few of us think could be the problem with your regulator and help you understand how it all works.

In the video he is adjusting the cracking pressure on the second stage from the hose end. It is the procedure we were discussing earlier that can be done with a flathead screwdriver on a Mikron. You will see this done in the video. When a new seat is installed this setting can change with use and if set close to the edge of freeflow it may cross into actual freeflow. This is what @rsingler was describing in post #33.

And this is why I asked if turning the knob stopped the problem since in essence that knob “detunes” the regular, making it harder to breathe but also mimics what would happed if the regulator was tuned as shown in the video.

So in short, I think your regulator may simply be tuned a bit too hot now after use and a simple adjustment (shown in the video) will bring it back in tune.

Although what you said is substantially correct, in reality fixing the free flow acting on the knob is not EXACTLY what happens when you fix it by moving the orifice slightly "in" using the flat screwdriver.
The knob does not change the relative position of seat and poppet, it just increases the preload on the spring pushing the poppet against the seat.
So, if there was no gap between the lever and the diaphragm, even increasing the force on the poppet does not bring it to a proper sealing against the orifice, as it cannot travel towards it. If instead the reg has the orifice in the proper position, the lever will have a minimal gap between its tip and the diaphragm meaning that the force exerted by the spring is fully effective pushing the poppet against the orifice.
In practice, acting on the orifice ensures the sealing without increasing the force on the poppet, and this ensures lower work for breathing. Acting on the spring through the knob, albeit producing the same effect of stopping the free flow, results in a slightly increased work of breath.
All that said, most of my SP 109 converted to balanced are tuned exactly as the reg described by the OP: with the knob "all out" they hiss very slightly, just a quarter of turn on the knob stops the hissing. I keep them this way as, in some conditions, a reg on the edge of free flowing can be useful.