Funny whistle breathing from long hose

[spectrum]

Does that first stage have dedicated primary ports? I know my Sherwoods have 2 of the 5 LP ports designaged as primary full flow ports for regulators. Not all ports are created eaqual and that could have an impact.

Pete

 

[DA Aquamaster]

On a piston first stage I would tell you to swap the spring end for end.

I hear that a lot. Since you have to remove the piston to do that, it indirectly addresses the lubrication problem by redistributing the lube on the piston stem o-ring. It has nothing to do with which way is up on the piston spring.

 

[idive2]

I just adjusted the intermediate pressure on an old first stage and noticed a difference in the noise I had been getting
from my second stage when below 700 psi tank pressure. The first stage IP had been set very low and I think this was
contributing to the second stage noise.

 

[looka]

Thanks everybody. I'll try and give you feedback

 

[Nemrod]

If you install an IP gauge at the regulator first stage and another at the second stage you can see that the longer the hose, indeed, the greater the pressure drop. If the IP is on the low side and depending upon the flow capacity of the first stage, and of course your demand, that drop can be more than you think. Check and make sure the hose has no internal damage, like a collapsed internal sleeve. Adjust IP to the high side.

N

 

[looka]

If you install an IP gauge at the regulator first stage and another at the second stage you can see that the longer the hose, indeed, the greater the pressure drop. If the IP is on the low side and depending upon the flow capacity of the first stage, and of course your demand, that drop can be more than you think. Check and make sure the hose has no internal damage, like a collapsed internal sleeve. Adjust IP to the high side.

N

Nemrod, thanks for your comment. The hose is new, so is the primary.
Breathing from only one reg in shallow water should not get even close to the limit in flow of my primary (which should support two divers breathing down to 100 meters).
I agree that the longer the hose, the greater the pressure drop at the end of it when i breathe. I just need to figure out how this is creating some sort of resonance. The reg works fine, but the noise is ear piercing and annoys the crap our of my buddies...

Thank for your comments.

 

[SangP]

I checked with my technician friend, he suspects an IP issue in the 1st stage too.

 

[DA Aquamaster]

. The reg works fine, but the noise is ear piercing and annoys the crap our of my buddies...

On a positive note, they know, with each breath you take that you are not out of air - and they know you are reasonably close.

I checked with my technician friend, he suspects an IP issue in the 1st stage too.

A caution here: Changing the IP will change the spring pressure and frequency of the resonance (to one you potentially can't hear) but it would not be addressing the underlying problem, if the problem is inadequate lubrication or some other factor causing the seat carrier/seat stem to oscillate.

 

[SangP]

On a positive note, they know, with each breath you take that you are not out of air - and they know you are reasonably close.

A caution here: Changing the IP will change the spring pressure and frequency of the resonance (to one you potentially can't hear) but it would not be addressing the underlying problem, if the problem is inadequate lubrication or some other factor causing the seat carrier/seat stem to oscillate.

DA my friend said check not change... he suggest a return to the store which serviced the reg too.

Lack of lubrication could be the culprit however, without a proper examination it could be 1 of a dozen reasons.

 

[silver02ca]

Had this problem on a reg i serviced a while back with a 6 foot hose. I changed the IP slightly and re lubed a couple of the dynamic orings.