Moisture in my first stage?

[ppatin]

About halfway through a recent trip I started hearing a weird hissing noise from my first stage whenever I took a breath through my regulator. I tried breathing through both my primary second stage and the octo and both produced the same noise from the first stage. My ability to breath through the reg didn't seem to be affected. Later on on the surface the divemaster listened to my reg as well and his theory was that it was the result of moisture in the first stage. His recommendation was to get the reg serviced once I got home. Since I have no idea what his actual equipment maintenance skills are I'm wondering if his theory sounds legit, and if so what do I do about it?

Whenever my regs were in the water they were obviously pressurized. When I got back to the boat I'd always dry the dust cap and immediately put it in place after I took my reg off of the tank so there's no way that more than a tiny bit of water could have gotten into my regulator unless someone secretly hated me and was sabotaging my equipment. I just got the darned things serviced prior to this trip so I'm not thrilled about the thought of shelling out more money on maintenance, but if there's salt water eating away at the insides of my first stage I guess I'd better deal with it sooner rather than later.

 

[LeadTurn_SD]

What make and model first stage? Piston or diaphragm?

I don't buy the "water in the first stage". Any moisture inside the first stage would be quickly dried by the very dry HP air moving through the stage. Any "leak" would be evident underwater by the presence of a bubble stream, and by "hissing" while on the surface.

If your first stage has started making a noise it did not previously make, you do need to determine the source of the noise. It is probably benign, but you should make sure.

The fact that you just had your regulators serviced is what would make me the most concerned.

If it did not "hiss" prior to service, but did soon after service, take it back in and tell the tech. Immediately post-service is usually the most common time for a regulator to "act up"; typically due to servicing errors or possibly defective replacement parts (seat, o-rings, etc.)

Best wishes.

 

[ppatin]

It's an Edge EXP, which is a diaphragm reg.

Thanks for the reassurance re: salt water. I'll give the shop that serviced it a call tomorrow. I knew it wasn't a leak since there wasn't any bubbling underwater.

 

[LeadTurn_SD]

Hi ppatin,

If the tech finds the problem, let us know... it may help someone else, and I'm interested to know the cause. I'm not familiar with the Edge EXP, but there are only a few internal parts that can produce a "hiss" during inhalation.

I hope you get it sorted out quickly.

Best wishes.

 

[herman]

Could the sound also be described as a squeel of some sort and only happens on inhale? That sound is not too uncommon in regs, it's just a resonance of the parts and is not too uncommon after servicing. Something as simple as installing the main spring 180 deg out of position than it was before (either way is OK, there is no particular end that has to go in first) can change things mechanically enough to cause it. You have a 50/50 chance of which end you use and maybe you just got "lucky" before. A slight change in mass of any of the parts first stage parts, many of which should have been changed during service is sometimes enough are enough to set up the correct conditions. I have a Mares MR-12 that just loves to sing like that. I would suggest you have it checked but if it's just a resonant "singing" it is anoying but not dangerous.

 

[ppatin]

Herman,

The sound only happens when I inhale. I wouldn't call it a squeal, but obviously that's kind of subjective. If the sound isn't moisture and I dived the reg for several days without issue then I figured it's probably not dangerous but I'll see what the shop says.

 

[HeatCker]

i just had the cracking pressure adjusted on my primary reg
the shop owner / tech mentioned that he would have to adjust the 1st stage as well
he said if he didn't tune the 1st stage to the primary it would make a noise when i breathed
possibly a resonance thing similar to what herman is talking about
anyhow to make sure everything is working correctly do as the others have suggested and take it back in

 

[LeadTurn_SD]

i just had the cracking pressure adjusted on my primary reg
the shop owner / tech mentioned that he would have to adjust the 1st stage as well
he said if he didn't tune the 1st stage to the primary it would make a noise when i breathed
possibly a resonance thing similar to what herman is talking about
anyhow to make sure everything is working correctly do as the others have suggested and take it back in

Herman is discussing harmonic resonance within the 1st stage, often related to the interaction of the main spring and the surfaces it rests on.

I believe your tech was referring to something else, but I'm not sure what...

Typically the 1st stage Intermediate Pressure (IP) is set when it is serviced, then the 2nd stages are "tuned" to this IP.

Cracking effort is adjusted at the 2nd stage, and depends on a stable IP.

The 2nd stages are "tuned" to the first stage, usually not vice versa. Usually the tech will set the IP to "factory spec", make sure it is stable, then tune the 2nd stages to the desired cracking effort.

If you are simply "fine tuning" the cracking effort on the 2nd stage, nothing needs to be done to the first stage (assuming the IP is stable).

Best wishes.

 

[HeatCker]

thanks for the info, i'm not reg savy so i probably got things backwards.
i'm not sure what the shop owner meant but he did say he would have to adjust the 1st stage or i may hear noises when i breathed.
i had the cracking pressure adjusted to help with cold water free flows, water temps are 56 F and dropping fast, soon to be in the low 40's, our dive season is almost over for this year.
i had a free flow earlier this year (spring time) and the owner said he would adjust the cracking pressure from 1 to 1.4 to try and help with a possible free flow.
does that make sense ??????

 

[Jim Lapenta]

I'd lower the intermediate pressure before upping the cracking pressure for cold water.