Mk 16 HP seat problem

[Kupu]

I am wondering what could cause my Scubapro Mk 16 high pressure seat to be worn out enough to need replacement only 38 dives after my annual service? I had it serviced this july and used it for a total of 14 days and 32 saltwater dives before both my second stages started a slow but steady free flow. Possibly the high pressure seat was not replaced during servicing? Or am I somehow doing something wrong to my reg?

I had noticed a very slight freeflow on my R380 octo on my first dives after service causing a tiny trickle of bubbles during the dive but at the time I figured it just needed to be detuned a bit. At the time I did not notice any problem with my S550 but it now has the stronger freeflow of the two second stages, not enough to prevent me from from finishing my dive trip but enough for me to put it in for service at an authorized dealer as soon as I returned to Manila.

I am now wondering if this this could be a design problem as I have had the same issue for each of the 3 years I have owned this reg. In the past it has been a smaller freeflow which has not shown up until near the end of the 80-100 dives per year I get in and I just figured it was normal. Now I see Mk16 discontinued and the Mk 17 with a new high pressure seat guide....Hmmmm, coincidence?

When I have mentioned this problem to my US local dealership when I take my reg in for annual service they have told me I am not doing a good job of rinsing my reg after use causing some salt water corrosion on the 1st stage. I feel I take good care of my reg, rinsing every day after my dives and taking care not to let water in past the dust cap and keeping the reg on a pressurized tank as much as possible during the day while on the dive boat in between dives.

Any thoughts?

 

[Lead_carrier]

Sounds as if they might be missing the setup just a bit.

 

[halocline]

Hopefully, DA aquamaster will see this and post something. If not, you might send him a PM; he'll have an answer for sure.

 

[DA Aquamaster]

I have never noticed any issues with the Mk 16 and they are in use by a few of the local dive teams in the area as well as by my most frequent dive buddy who also does 130-150 dives per year.

But then I also noticed the Mk 17 literature that mentions a new HP seat guide and use of a new seat material to prevent delamination. It is enough to at least get one wondering if perhaps there was a problem with at least one batch of bad seats that were produced.

The IP needs to be checked to ensure that it is in fact a first stage problem, and if so, what the problem may be. If there is IP creep, then the HP seat is at fault. If the IP is just high but with no creep, it would most likely be a case of salt crystal buildup in the ambient chamber. This can increase the IP by 10 to 20 psi and would be enough to initiate a freeflow in the second stage. This is not all that common in the Mk 16 as the holes are large and the chamber is relatively easy to rinse, but I have seen it occur on other diaphragm first stages that are rlatively hard to rinse (Dacor Quantum comes to mind).

If the IP is normal, within range, and creep free, then it is a problem with the second stage adjustment. A seating groove develops in the second stage soft seat as the seat breaks in and if the tech does not properly anticipate and compensate for this effect, a slight free flow will develop after several dives and the reg will need to be adjusted to stop the freeflow.

It sadly would not be totally unheard of for a tech who screwed up the adjustment to point the finger at the user and claim it was due to improper rinsing.

 

[jumbo]

Bummer news, I would say it is not a design problem the mk 16 has a long history of exceptional use. The mk 16 is notable for its high performance over a very long period of time, for example if your left for some remote part of the world and would not be able to have your system serviced for a few years, you would want to bring a mk16.

If both your second stages are free flowing there could be a number of reasons why, if it was caused by the first stage it would have to be your ip, did you test it?

Beyond that, the two different styles of second stages both leaking is not normal, hopefully your lds did not assemble both regs incorrectly or used old seats for both second stages. I would be willing to bet that is not the situation.

Not washing your equipment is probably not the reason for your problems, the mk 16 is a sealed first stage meaning not water should be in there. And salt water corrosion on the first stage would have no effect on the performance of your first stage. If you rinse your gear even one out of ten dives you should have no problems for years!

To the solution, since you have had problems for 3 years now I can only hope that your reg tech is not that bad, and in practical reality, you should be able to get thousands of dives with out a problem from that reg.

If it was me I would send it back to scubapro, they will run a gamet of test on it and assemble it absolutely correctly. Or they may find out that there is a defective problem with the housing of your first stage and replace it.

Good luck-

JUMBO

 

[Kupu]

The IP needs to be checked to ensure that it is in fact a first stage problem, and if so, what the problem may be. If there is IP creep, then the HP seat is at fault. If the IP is just high but with no creep, it would most likely be a case of salt crystal buildup in the ambient chamber. This can increase the IP by 10 to 20 psi and would be enough to initiate a freeflow in the second stage. This is not all that common in the Mk 16 as the holes are large and the chamber is relatively easy to rinse, but I have seen it occur on other diaphragm first stages that are rlatively hard to rinse (Dacor Quantum comes to mind).

If the IP is normal, within range, and creep free, then it is a problem with the second stage adjustment. A seating groove develops in the second stage soft seat as the seat breaks in and if the tech does not properly anticipate and compensate for this effect, a slight free flow will develop after several dives and the reg will need to be adjusted to stop the freeflow.

It sadly would not be totally unheard of for a tech who screwed up the adjustment to point the finger at the user and claim it was due to improper rinsing.

The service tech said the problem was a HP seat that needed replacing, resulting in high IP. This is the main reason for my post, how can a HP seat be so worn as to need replacing after only 38 dives? I have a hard time understanding how this could be my fault after so few dives even if I completely abused my reg, which is certainly not the case. And if it is unlikely to be a design flaw, then I am very suspicious my LDS had a terrible service tech give my reg the annual overhaul. But in the past they always have pointed the finger at me anytime I have a problem. If user error can resonably be ruled out for this particular problem, then this is the final straw, I am finding a new shop to service my reg. But since I bought my reg from them specificly because I wanted "local LDS service" I want to be sure I am not jumping to conclusions.

I think it could be likely the free flow problems I have experienced in the past are related to the S550 second stage being too finely tuned and then having the seating groove develop since the free flow developed very slowly after numerous dives and was not nearly as pronounced. I don't recall the R380 freeflowing before, and of course it recieved much less use than the S550.

Thanks for your reply.

 

[Kupu]

Bummer news, I would say it is not a design problem the mk 16 has a long history of exceptional use. The mk 16 is notable for its high performance over a very long period of time, for example if your left for some remote part of the world and would not be able to have your system serviced for a few years, you would want to bring a mk16.

Not washing your equipment is probably not the reason for your problems, the mk 16 is a sealed first stage meaning not water should be in there. And salt water corrosion on the first stage would have no effect on the performance of your first stage. If you rinse your gear even one out of ten dives you should have no problems for years!

To the solution, since you have had problems for 3 years now I can only hope that your reg tech is not that bad, and in practical reality, you should be able to get thousands of dives with out a problem from that reg.

If it was me I would send it back to scubapro, they will run a gamet of test on it and assemble it absolutely correctly. Or they may find out that there is a defective problem with the housing of your first stage and replace it.

The advertised reliability of the Mk 16 was a main reason why I decided to buy it for a first stage, along with resonable cost. I have been spending as much time as possible backpacking around SE Asia and Central America with diving as my main objective, which does lead me to some areas where reg service can be hard to find and I need a reg that can take the conditions. Overall I am still very happy with my Mk16/S550, it has been fairly dependable. This is the first time I have had to have it worked on in between annual service. Perhaps getting a new service tech will settle any issues I have.

Although I think it is very unlikely to be the cause of my present problem, I am thinking water could still enter the sealed 1st stage if care is not taken? Not that I do these things, but for example, if the reg was soaked with the dust cap removed or lots of sea water was splashing into the boat and on the reg in between dives while the reg is removed from the tank without the dust cap on.

If I have further problems, sending it to ScubaPro sounds like a good option.

Thanks for your help.

 

[jumbo]

I would rule out user error, unless you soak your gear for long periods of time.

Some people believe you should soak your first stages. But in my experince I would not recommend soaking your regs, a good spraying from a hose should do the trick. I have had problems with regs that have been soaked for periods of time, even with the dust cap on, it is not water proof.

Good luck, sounds like you got a really cool thing going with all that back packing and diving.

JUMBO