Regulator whistles at depth

[Lightning Fish]

Hello:

I was at 50-70 fsw the other day and my regulator started whistling. (Sounded like an old Eric Clapton tune) :54:

Seriously, when I breathed in I could hear a whistle, much like the sound you get when you blow over the top of an empty bottle. The regulator I have is an Aqualung Titan LX. The whistling occured regardless of where the venturi switch was positioned.

Can anyone explain what was happening and how to prevent it from happening?

Cheers,
Bill.

 

[Diver0001]

Hello:

I was at 50-70 fsw the other day and my regulator started whistling. (Sounded like an old Eric Clapton tune) :54:

Seriously, when I breathed in I could hear a whistle, much like the sound you get when you blow over the top of an empty bottle. The regulator I have is an Aqualung Titan LX. The whistling occured regardless of where the venturi switch was positioned.

Can anyone explain what was happening and how to prevent it from happening?

Cheers,
Bill.

Hi Bill,

This kind of whistle is typically caused by a harmonic in the air flow. like blowing across the top of a beer bottle. In some cases it can also be caused by the spring in the poppet assembly of the 1st stage vibrating but then (IIRC, it's been a while) then it sound more like a moan than a whistle.

In any event it's unlikely to suddenly get any worse. If it's irritating then take it back for warranty service and get them to change something. Sometimes just taking it apart and putting it back together will stop it. Other times you may need to lubricate the spring or change the LP seat on the poppet. Anything that changes the dynamics of the airflow might stop it.

Also are you sure it's coming from the 2nd stage? If you're sure it's coming from the second stage you might want to get them to look at the actuating-lever. It could be too low causing the LP seat to not open wide enough. Rasing the lever, even a tad might make it go away.

R..

 

[Damselfish]

I had a situation where a o-ring was left out of my first stage when serviced, causing pressure to the second stage to be way too high. It was a long time ago but as I recall it was more of a honk/moan type noise than a whistle, and it got better with depth which makes sense. Point is, it seemed at the time like just an annoying noise from a badly tuned 2nd stage, when I found out the real problem I was like "yikes." Don't ignore...

 

[rescuediver009]

Hi Bill,
Other times you may need to lubricate the spring or change the LP seat on the poppet. Anything that changes the dynamics of the airflow might stop it.

R..

In servicing regs I have never known a spring that required lubricating. Second, even if you do lubricate the spring, you are not changing the dynamics of the airflow as it is behind the LP seat, unaffected. :monster:
If while pressurized, you shake your second stage and hear a rattling it is definitely the actuating lever. This once again is not likely the problem as the reg would breath extremely hard with this symptom.
I would say just take it back as there my be an intermediate pressure creep, or improper seal on the LP.

 

[Lightning Fish]

How about a little history on the reg. It's brand new, Aqualung Titan LX, only has 4 dives on it. After the third dive I took it back to the LDS as it was quite difficult to breath from below, let's say 60-70 fsw. The tech checked it out and the IP is fine. The cracking resistance was set on the hardest setting so he decreased it closer to the easiest setting. It is a little easier to breath off of now.

This was the first dive after the cracking resistance was decreased. The whistling occurs when I breath in and started after I hit 45 feet. I can't remember if it stopped on the way up after a certain depth or not. It doesn't occur on every breath. I think it happens towards the end of my breathing in. It does not sound like a moan or "farting" as regs do on the surface.

Rescue diver, when you say "improper seal on the LP", are you referring to the second stage or the lower pressure section of the first stage?

As the cracking resistance is adjusted, can that affect how the diaphram sits?

Cheers,
Bill.

 

[Diver0001]

In servicing regs I have never known a spring that required lubricating. Second, even if you do lubricate the spring, you are not changing the dynamics of the airflow as it is behind the LP seat, unaffected. :monster:
If while pressurized, you shake your second stage and hear a rattling it is definitely the actuating lever. This once again is not likely the problem as the reg would breath extremely hard with this symptom.
I would say just take it back as there my be an intermediate pressure creep, or improper seal on the LP.

Yep. My bad I was thinking of something else.

R..

 

[Tiny Bubbles]

How much pressure is in the tank when the whistling or honking or whatever starts? My aqualung 1st stages honk while inhaling if the tank pressure gets real low. And the noise does sound kind of like blowing over an empty bottle. It's normal for them to do that.

If the tank is full when it does it, my first guess would be something is restricting the airflow into the 1st stage, like the tank valve not being fully open, or a plugged filter or something... That could make the honking noise mostly toward the end of the inhale, and may be aggravated by depth.

-tiny-B.

 

[rescuediver009]

I meant that it could be that the low pressure seat in the second stage
is not being pulled away from the cone far enough. The cone puts
pressure on the rubber seat and seals it when you are not breathing.
When you inhale the diaphragm collapses and pushes the lever down in
turn pulling the seat away from the cone. If the seat is not pulled
away from the cone far enough (we are talking thousandths of an inch
here) it could make a farting noise.... This is one of those things
that you need to explain to your technician and have him look at it. It is really hard to identify the problem without actually seeing the equipment. The easiest thing to do it is just say straight up " I bought this here, it is under warranty get me a new one!" (in nicer words). Personally if the reg I just bought was like yours I would want a new one especially if it was new, you never know what else is wrong with it.

 

[will_tekkie]

the problem showed here is quite interesting..i´ve heard it a couple of times ago..but explanations always are quite unclear..we can say ( as said above) for example the problem is related with the HP seal (improper seal ), maybe joined with a kind of dynamic vibration of it that cause an unstable IP and noise...the HP filter can be checked as well as a possible cause..a dirty or non well manufacturer one could be the noise source as well...we have to keep in mind than the reg is working in critical flow so mass flow downstream the valve is constant....