Seaquest Pro QD+ inflator hose loose

[chinadan]

Hi-

I have recently noticed that the inflator hose on my BCD was coming off when I pulled on it. Note that this BCD has a dump valve on the left shoulder which gets activated through a cable inside the inflator hose. This is how I found out (on land) that the corrugated hose could become detached from the snout of this valve. The hose is secured on the valve with a tie wrap. My dive shop easily corrected the problem with a stronger, more tightened tie wrap.

Question is what would happen under water if the inflator hose became loose? Would water enter the BCD? Could it still inflate? In any case, it seems to me to be a dangerous design flaw (especially since the dive shop noted that they had quite a lot of these repairs) and remember, you are supposed to pull on the inflator hose to dump air!

Any ideas?

 

[rescuediver009]

First things first, the pull dump is designed as an alternative dumping mechanism. The reason that the hose came loose is likely due to excessive pulling. Many people who do what you describe, also dislodge the gasket inside the inflator.

As far as what would happen if it became loose, first all the air would bleed from the bladder, depending how far off it comes, then you will loose all neutral buoyancy. try not to use it all the time thats all. If anything the PRO QD has rear pull dumps as well. Use those.

 

[chinadan]

First things first, the pull dump is designed as an alternative dumping mechanism. The reason that the hose came loose is likely due to excessive pulling. Many people who do what you describe, also dislodge the gasket inside the inflator.

As far as what would happen if it became loose, first all the air would bleed from the bladder, depending how far off it comes, then you will loose all neutral buoyancy. try not to use it all the time thats all. If anything the PRO QD has rear pull dumps as well. Use those.

Actually, I never use this pull dump and was just curious after reading about it in the manual. I pulled with normal force and the whole hose just slipped off the plastic snout completely, revealing the steel cable on the inside.
In fact, you can't pull any further due to this steel cable, so the only force on the hose-valve connection comes from elongating the hose to overcome the slack of the steel cable.

With the new tie wrap, I can not pull hard enought to get it to come off. As this is a feature of the BCD, I believe that it is a weak-point in the design, with potentially grave consequences. I would be surpirsed if Seaquest actually has a pull-test in their factory, at least they do not warn about excessive pulling in the manual.

If it is prone to failure, why have it at all? This BCD could do well without this mechanism and the lack of this feature would stop curious minds from pulling on the hose at all.

Having your life depend on a tie wrap (obviously not fully tested) is scary and I can imagine there are other ways to fasten the hose to the dump valve (e.g. 2 tie wraps, positive lock)...

100% of all time I use the normal deflator button rather than any pull dumps unless I do a head-first descent.

I just thought I bring this up in case other owners have encountered this, or, are about to (hopefully on land).

Maybe SQ wants to hear about it...

 

[baitedstorm]

I have the exact BCD, which is now almost a year old. Same thing happened to me while shore diving, thankful I wasn't on my normal drift dive or I would have had to ditch my weight pockets. The hose came loose and I wasn't able to add air or keep air in my BCD. I couldn't stay above the surface and had no choice but to swim on the bottom until I was shallow enough to stand. I had some major concerns also and took my BCD back into the LDS I bought it from. Ironically, they didn't seen to think it was all that big of a deal (which ticked me off). They put a new zip tie on it and sent me on my way. Of course I needed to see what was going on inside so I cut off their new Zip tie and to my suprize found that the little metal cable had broke into two pieces. I called the LDS back, they said the would replace it even though I didn't use that feature. I was also told I'm being to rough on he hose when I'm dumping air on my descents and that I should stop "YANKING" on the thing so hard.

I now keep the proper equipment in my "save-a-dive" kit to fix this should it ever happen again.

 

[jbichsel]

This "design flaw" is not unique to SeaQuest. Other manufacturers use the same design.

I also have a Pro QD+ but have not had this problem. I hardly ever use this feature though. I usually use the bottom right pull dump when fun diving as I'm head-down. When teaching I use the LP hose elevated but just use the deflator button.

 

[rescuediver009]

Any of the rear pull dumps are fine. Because of the fact that they are pulled straight out, they do not put any tensile stress on the threads or glue of the BCD. It is not a flaw. The problem I explained earlier occurred on a Zeagle, and any BC with a Corrugated hose is susceptable to this problem. Just take it as a learning experience and don't over analyaze it. You have much more important things to be worried about.

 

[Scubaroo]

If it is prone to failure, why have it at all? This BCD could do well without this mechanism...

It's a built-in failure point. You can probably get a plain elbow to replace the pull dump.

 

[RICHinNC]

Before i went to the dark side and got a bp and wing i had an sq pqd. I used the hose dump ALL the time and never had a problem. You dont have to pull hard at all....everyone i have ever talked to with problems were pulling like there was no tomorrow....not needed. Just enuf to let air out and stop.

my lds sells them and hasnt seen a lot of problems.....and when i bought the thing i called sq....they said it was designed to be used that way....
go figure

 

[Druid]

I have a SeaQuest ProQD, and like RICHinNC above, I use the hose all the time to dump air. Never had a problem either. I've just been to check my bc and there's no sign of it coming loose. Checked my son's ProQD too, that's fine but he tends not to use the hose to dump air. My wife has a SeaQuest Eva, same mechanism as the ProQD, also secure but it's only a couple of months old.

I can't understand how the hose can come loose in normal use. The dump valve is connected to the inflator valve by means of a cable, which does not stretch. As you pull the inflator valve corrugated hose does stretch, but only by the distance required to release the dump valve - 20mm? The corrugations in the hose are designed specifically for that purpose, to allow the hose to stretch. Maybe the hose is too short, or the cable too long (from a different bc maybe?)

The system is used in almost all the bcs I have ever seen, so it's not a SeaQuest design flaw :06:

 

[chinadan]

I have a SeaQuest ProQD, and like RICHinNC above, I use the hose all the time to dump air. Never had a problem either...etc

As you mentioned correctly, the corrugated hose elongates to take up the slack of the steel cable inside which eventually triggers the dump valve. Of course, this pull force has to be taken up by the connection between hose and dump valve (force and reaction).

What happened on my BCD is that the whole hose slipped off the snout of the dump valve. The snout is smooth and has one circular ridge. The hose slides over that ridge, onto the snout and is then fastened with a single tie wrap behind the ridge. Supposedly, this tie wrap does not change its diameter and is therefore stopped by the ridge on the snout.

In my case, the plastic tie wrap was not tight enough, therefore opened just enough that it could slip over the ridge.

As mentioned in earlier posts, this, if it happenes under water, prevents inflation of the BCD and lets water enter the BCD.

While this design is common and, if properly tested during production and check-ups, is probably safe there are simple design concepts that prevent such a potential failure alltogether. As a mechnical engineer I would have selected a solution that tightens more as you pull, thus ensuring absolute safety (imagine a seal in a pneumatic cylinder that, as the cylider gets pressurized, has the air pressure acting on the seal, pressing it even closer to the sealing surface).

Anyway, problem is fixed now, I am warned and was hoping to warn other people about this too.