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It's that time again, Dump Valves...

Discussion in 'Dry Suits' started by JPasquette, Jan 31, 2018.

  1. JPasquette

    JPasquette New Member

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    Yes guys, we all know what's coming!

    It's that time again where some idiot asks about the differences in everyone's experience between the Apek high profile and low profile auto-dump valves. I am replacing my D1 this month and seeing as I have the option between the two I'm wondering what people think.
     
  2. nickb

    nickb Active Member

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    Low profile every time.

    The high profile dumps were recommended by certain divers about 10 to 15 years ago because of issues with some early low profile ones but that hasn’t applied for a long time.

    Those same divers were also saying that SiTech dumps were better. In my experience, and I’ve had a few, that is also bollocks.
     
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  3. nickb

    nickb Active Member

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    Another thing worth considering is that a SiTech dump will fit into an Apeks sealing ring, which could save a dive in a pinch. The opposite does not apply as the hole is smaller and an Apeks will not fit.
     
  4. Wibble

    Wibble Fish don't talk
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    Having seen a guy this weekend who nearly lost his dive because of the 'flimsy' Scitech high profile dumps disintegrating (he only dived because by a miracle the skipper had a spare drysuit that fitted him!) -- I'm rather in agreement with @nickb.

    To the extent that I think I'll look around for a replacement Apeks and pre-emptively replace it.
     
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  5. Tel

    Tel Super Moderator
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    I've had nothing but trouble with SiTec so any suit that comes in with them gets auto-swapped for Apeks.
    Talking of which here's a handy graphic showing why the the older Apeks high profile should also be auto-swapped.
    [​IMG]
    The difference between a Mk1 and Mk2 is not massive, but Mk1's are poo and has a nasty habit of the stop breaking
    meaning no idea if fully open or closed and yep you guessed, they get auto-swapped.

    So in essence the solution is an easy one:) Either you have a Mk2 Apeks now or if not it's time to swap what you have
    for a Mk2.

    [​IMG]
     
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  6. JPasquette

    JPasquette New Member

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    I have a si-tech at the moment, so am swapping that for sure! Just wondering whether to go high or low profile with the apeks! That graffic helps a lot! Are there any advantages of the high profile over the low? I'm relatively new to dry sit diving!
     
  7. Tel

    Tel Super Moderator
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    The high profile is an old unit now and is often found on older second-hand drysuits.
    It's not as efficient in use as the graph shows and not exactly helpful when putting on
    a BC or wing where it can get snagged.

    It would be very rare to fit this by choice as the Mk2 low profile is vastly superior.

    BTW swapping valves is easy, but the Sitec is fitted to a smaller diameter hole. This
    it has to be made bigger to fit and depending on what is there now, sometimes it's better
    to add a backing pad after cutting.
    [​IMG]
     
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  8. Wibble

    Wibble Fish don't talk
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    Thanks @Tel. For completeness, what sort of price would one pay for a Mk2?
     
  9. Wibble

    Wibble Fish don't talk
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    Google say £50
     
  10. Tel

    Tel Super Moderator
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    About £45-£50 retail, but they do come up on ebay etc. and are often discounted quite a bit.
    I've bought new in the past for £20.
     
  11. phantomlurker

    phantomlurker Member

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    Interesting. I'm pretty sure I need one of these to bring my suit up-to-date...
    Time to get searching for a bargain!
     
  12. JPasquette

    JPasquette New Member

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    So if I get a suit that comes with a high profile, I can swap it straight for a low profile one without needing to alter the hole? Is that correct?
     
  13. Tel

    Tel Super Moderator
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    Yep :)
     
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  14. Wibble

    Wibble Fish don't talk
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    Scitech and Apeks have different sized holes.
     
  15. Tel

    Tel Super Moderator
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    Yeah already said that in Post #7

    If he swaps a high profile Apeks for a low profile Apeks Mk2 it will be the same hole.
     
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  16. JasonP

    JasonP Member

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    Why? That graphic shows that the old valves have a flow rate of 150l a minute. That's a huge amount of gas, way more than you'll ever need.

    Sent from my LG-H990 using Tapatalk
     
  17. Tel

    Tel Super Moderator
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    An uncontrolled ascent be that by diver or kit error and a solution that works 50% quicker - why not?

    In his case though I believe he has the Mk1 which is pants and why he's going for a Mk2 :)
     
  18. phantomlurker

    phantomlurker Member

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    I see no reason not to change it, especially as both the Dive Officer and the Lead Instructor advised me to do so, along with the logic for doing so. The LI then tracked down an eBay bargain and pointed it out to me rather than adding it to kit stores. And is going to show me how to make a valve removal tool.

    Seems silly not to upgrade my suit for less than £20

    Indeed I do have a mk1 low profile, so it's being swapped for the Mk2 for potential breakage rather than gas volume reasons.

    Cheers @Tel, you're the best BSAC LI I know ;)
     
  19. JasonP

    JasonP Member

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    Because it won't make any difference?
    I would change it in that case.
     
  20. Tel

    Tel Super Moderator
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    You forget that before the ascent becomes a rapid one the valve is still working (if open)
    without any action from the diver. That means 50% more gas will vent in the same time
    and a greater degree of control or potential for recovery from the diver. In essence the diver
    gets more of a chance to sort by a factor of 2 and stop the rapid happening with a Mk2.
    That might not have been possible with the older high profile version. .

    Similarly in a rescue situation doing a CBL when three hands are needed, the Autodump
    is usually left to itself to work while the rescuer is dealing with grip of casualty with one
    hand and and inflate/deflate of BCD with the other.

    Given that the rescuer may not have any idea if the other diver is over-weighted or even
    know the diver at all, again what should be a controlled ascent may have the potential for
    going out of control if air doesn't dump fast enough.

    The vast majority of the worlds drysuit divers are not dive ninjas, just normal. They will
    mess up and have the odd bad day when a more efficient dump could make the difference
    and why old vs new is not even a question that should be on the radar.
     

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