First stage failure maybe...?

[Bill Devitt]

Hi,

On a recent dive, the second of the day using the same gear, I had a problem at 18m after about 15 mins diving. I went to take a breath and got virtually nothing. I sucked real hard and managed to get some air, about 10% of what you would expect. I was right next to the dive master so I remained calm and switched to my octopus. Same problem, about 10%. I tried to see what would happen free flowing and nothing. I switched again to my main regulator and sucked hard again and got about 10%. I then signalled to the dive master that I had an issue. I used his spare reg until we got safely to the surface. I never got an explanation of what went wrong...language barrier maybe, he just shrugged his shoulders. Anyone got any insights into what went wrong? I am guessing it was dirt / debris in the tank that came up and partially blocked the valve. I got the impression that the gear I was using was poorly if ever serviced.

Thanks for any feedback

 

[Fibonacci]

It’s possibly corrosion from inside the tank causing a partial blockage, but the dip tube is supposed to prevent that.
More likely from the other end, clogged filter caused by poor rinsing/lack of service...

 

[drk5036]

I’m not sure we really know enough. Where was this when it happened?

Often when this happens, the tank valve isn’t fully open. Someone checks your tank, thinks it’s closed when it’s fully open. Then they completely close the tank, and turn it “back” a quarter turn, resulting in a tank that is only slightly open. You can’t tell on the surface but it becomes obvious at depth.

 

[Bill Devitt]

Thanks Guys. I did check that it was open myself but I get your point. Surely If the valve was only slightly open I would have noticed it right away and not just after 15 mins? I was kinda off the beaten track in the Philippines. On another dive the next week (different place) I watched the boat guy check the BCD's and saw him ignore a faulty BCD. It jammed and fully inflated the vest if you touched it. He only changed it when I pointed it out. Safety did not seem to be top of the priority list sadly at a lot of the places I dived there.

 

[Neilwood]

Hi,

On a recent dive, the second of the day using the same gear, I had a problem at 18m after about 15 mins diving. I went to take a breath and got virtually nothing. I sucked real hard and managed to get some air, about 10% of what you would expect. I was right next to the dive master so I remained calm and switched to my octopus. Same problem, about 10%. I tried to see what would happen free flowing and nothing. I switched again to my main regulator and sucked hard again and got about 10%. I then signalled to the dive master that I had an issue. I used his spare reg until we got safely to the surface. I never got an explanation of what went wrong...language barrier maybe, he just shrugged his shoulders. Anyone got any insights into what went wrong? I am guessing it was dirt / debris in the tank that came up and partially blocked the valve. I got the impression that the gear I was using was poorly if ever serviced.

Thanks for any feedback

Sounds like a poorly serviced reg to me - as @Fibonacci says there is a dip tube on the valve that should prevent any corrosion blocking the valve - (watch the description of the valve on this clip). This is the reason why I will always take my own regs if I intend to dive. I know the state of my regs and if anything goes wrong I only have myself to blame.

I certainly would not want to dive with them again as they don't seem to care about safety if the equipment they use is so shoddy.

 

[johndiver999]

Thanks Guys. I did check that it was open myself but I get your point. Surely If the valve was only slightly open I would have noticed it right away and not just after 15 mins? I was kinda off the beaten track in the Philippines. On another dive the next week (different place) I watched the boat guy check the BCD's and saw him ignore a faulty BCD. It jammed and fully inflated the vest if you touched it. He only changed it when I pointed it out. Safety did not seem to be top of the priority list sadly at a lot of the places I dived there.

No, you can have the valve partially open and if you are demanding air slowly and calmly, you may not detect the problem. However, as the tank pressure drops, the valve restriction can affect air flow and it is possible that when you first feel the restriction, your first tendency is to suck real hard and fast to "test it" and then you might really be able to "feel" the restriction due to the depth, the lower supply pressure and the attempt to induce a high air flow.

A partially open valve is the most likely suspect, but debris in the tank could also definitely be the cause as well.

 

[Bob DBF]

but the dip tube is supposed to prevent that.

Assuming it has one, if it's a slap dash outfit, there are numerous causes and combinations of causes that can culminate in this problem. I would suggest spending more and finding better dive ops, or realize that the wheels could fall off at any moment, and dive accordingly. I'm not against either course of action, it would depend on the up side of the equation.


Bob

 

[Bigbella]

I agree that the answer could have been as simple as a partially open tank valve; a clogged sintered filter; or, more likely, long-term corrosion of the first stage, from saltwater intrusion. A friend, whose regulator I finally serviced, had complained about something similar, while also on a foreign trip. Upon disassembly, it looked as though her first stage contained what resembled blue strands of loose leaf tea.

I think that it would benefit most divers, to see, first hand, what shoddy or lackadaisical maintenance, can do to a regulator; but, realistically, repair is typically done behind closed doors. Regardless of its substantial heft, brass is a rather soft metal, and very prone to electrolysis and overall corrosion; and should pitting ever occur to critical sealing surfaces, where numerous o-rings and the high pressure seat are located, the function of that first stage could always be impaired, to some degree.

A late lamented shop, where I worked while at university, referred to those regulators as being "possessed." The IP would mysteriously creep, even after fine adjustment; breathing could be irregular; and one client described a lovely experience at depth as attempting to "suck a ball bearing through a collapsing paper straw . . ."

 

[W W Meixner]

Hi,

On a recent dive, the second of the day using the same gear, I had a problem at 18m after about 15 mins diving. I went to take a breath and got virtually nothing. I sucked real hard and managed to get some air, about 10% of what you would expect. I was right next to the dive master so I remained calm and switched to my octopus. Same problem, about 10%. I tried to see what would happen free flowing and nothing. I switched again to my main regulator and sucked hard again and got about 10%. I then signalled to the dive master that I had an issue. I used his spare reg until we got safely to the surface. I never got an explanation of what went wrong...language barrier maybe, he just shrugged his shoulders. Anyone got any insights into what went wrong? I am guessing it was dirt / debris in the tank that came up and partially blocked the valve. I got the impression that the gear I was using was poorly if ever serviced.

Thanks for any feedback

Bill...

From the little we know...it sounds like poorly maintained...assuming rental...equipment...

Look into the inlet of the first stage...on most first stage regs the sintered filter is visible...if it's covered with vertegre...usually a blue colour...it's a clear indication the 1st stage inlet is plugged...doesn't take much salt water intrusion for this to happen...

Best way to avoid this problem is to travel with your own gear...doesn't have to be every piece of gear you own...just your primary components that you know and trust...and ensure you rinse everything...gear/reg bags included...before anything starts to dry...as soon as you get back to your hotel...

When away diving in third world countries...assume your rental gear has not been adequately serviced and maintained...leaking BCD's being held together with zip ties...poorly performing regs...broken fin and mask straps...deteriorated wet suits...are all common...and far too often the rule...rather than the exception...further...don't be fooled by...'''no speak English''...in most cases it's a ruse...these operators for the most part deal with Westerners 365 days of the year...

Taking your own gear will solve this problem permanently...

W.W...

 

[Bill Devitt]

Again, many thanks for all the responses, ver helpful. I will purchase my own regulator for future use and triple check the valve is fully open. I travel extensively and tend to fit in dive trips along the way as opposed to traveling specifically to dive which is why rental equipment is the option. I have come across too many instances of poorly serviced gear over the years so it is time to change the way I travel and dive.