Are you more likely to experience a freeflow on your second dive? Or if you've dodged the bullet the first time, does that indicate you should be ok on dive #2?
Freeflow
- Thread starter jiveturkey
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
IMHO, whether it's the first or second dive isn't relevant. The number one cause of free-flows in cold water is over-breathing the reg - which could happen on either dive. Pre-breathing the reg on the surface in below freezing temps, hard breathing underwater while hitting the inflater, purging the reg, high IPs, descending into a colder thermalcline... all can contribute on either dive.jiveturkey:
As I discovered by going from a K-Mart reg with lots of free-flows, to my Atomic M1 (environmentally sealed) with no free-flows, the quality of the reg is everything.
Manta Aria
Contributor
- Messages
- 182
- Reaction score
- 1
- # of dives
- 50 - 99
This is going to sound stupid :fruit: , but have you played with your Venturi Assist? The very few times that I have freeflowed has been due to my VA being maxed by me accidently touching it. A quick flip of the switch and I'm golden again. Does this happen to you often? If it keeps doing it, have someone who's qualified look it over and service it if need be. Or worst case scenario buy a new, higher quality reg.
Until then,
Dive Safe
-Manta
Until then,
Dive Safe
-Manta
There are a wide variety of things that will cause a free flow.Manta Aria:
Not all rigs have an adjustable venturi assist and a freeze up free flow most likely will not be cured by the flip of a switch like an over pressure flow can.
The age of the rig and just because it is a top quality unit doesnt mean it isnt going to freeze and free flow. A lot has to do with how it is tuned and treated before and during the dive. Any reg can freeze and/or free flow if you dont treat it right.
A shop should be advised that the reg is going to be used in freezing conditions so it can be tuned properly. They can have different settings between summer and winter set-ups.
Even with summer temps one can still freeze a reg. We have areas that will have 80df surface temps and just above freezing bottom temps that will help get one to open up.
Gary D.
My one freeflow so far was dive 2. I was just doing my OW/DS certs, sucking air like a race horse 
Fresh water, mid-30s.
Cold water + cold SI + sucking air down + bad tuning (Sherwood Maximus -- I had it set like I use in warm water) = Yes, even a good reg can freeflow.
When I chatted with other locals, albeit just a few, I came away with the feeling that it might be more likely on the second dive, though this was not a large sample by any means.
Fresh water, mid-30s.
Cold water + cold SI + sucking air down + bad tuning (Sherwood Maximus -- I had it set like I use in warm water) = Yes, even a good reg can freeflow.
When I chatted with other locals, albeit just a few, I came away with the feeling that it might be more likely on the second dive, though this was not a large sample by any means.
markfm:My one freeflow so far was dive 2. I was just doing my OW/DS certs, sucking air like a race horse
Fresh water, mid-30s.
Cold water + cold SI + sucking air down + bad tuning (Sherwood Maximus -- I had it set like I use in warm water) = Yes, even a good reg can freeflow.
When I chatted with other locals, albeit just a few, I came away with the feeling that it might be more likely on the second dive, though this was not a large sample by any means.
The only free flow has been a 1st stage not a second stage so the adjustment wont help. The only thing you can do is keep your gear serviced. If you dive cold water all the time. Make sure your tech know this so they can adjust your reg properly. I had my Intermediate pressure backed down and the seat adjusted now i have zero problems. Also make sure your reg is environmentally sealed. Happy diving. My free flow was on my second dive. warm moist air on the surface in between dives. The air temp was 85 the bottom temp was 38-42.
There are 4 basic causes of what people would consider a "freeflow".
1. Diver error - the reg is dropped in the water purge cover down and physics does the rest. On regs with an adjustable flow vane/venturi assist, setting the switch to "min" should creqate enough back pressure to stop it on it's own. With the switch in "max" it won't stop until yopu put your thumb over the mouthpiece to block the flow.
2. Excessive intermediate pressure. This type of freeflow is generally slight (at least in the early stages) and can be observed as a very slight hissing sound a few seconds to a few minutes after your reg is pressurized. It's caused by a leaking high pressure seat and if the reg is left pressurized while no one breathes off it, the leak will cause the intermedate pressure to slowly increase until the excess pressure vents though one of the second stages. In severe cases, the freeflow will be noticed under water as the intermediate pressure will incease enough in the few seconds between breaths to cause a freeflow. The condition is always progressive and that point, it is about to get bad enough to continuously freeflow.
3. A leaking second stage seat - This can be the result of improper adjustment either initally or in the form of the tech failing to properly anticipate the normal development of a seating groove. It can also be the result of the seat wearing over time. If the reg was recently serviced, it's probably the former and if it has been a year or so, it's probably the latter. In either case, you need take it in for adjustment or service.
If you have a second stage with an adjustable inhalation effort effort, you can solve the problem, at least temporarily, by turning the knob in slightly farther. It it is due to wear of the seat, you will eventually run out of adjustment and will need to take it in for service.
This freeflow differs from number 2 in that it will occur immediately upon pressurizing the reg with no delay.
4. A cold water induced "freeze flow" - This most often results from the first stage freezing up due to the cooling effect that occurs in the first stage as the high pressure air flowing through it absorbs the heat needed for it to expand. Cold water kits, usually in the form of either sealed diaphragms, oil or silicone filled ambient chambers or anti-stick or insulating coatings on key parts, help significnatly but are not always bullet proof.
Good cold water technique is a good idea if you are diving water colder than about 50 degrees. This includes:
A. not using your power inflator to fill your BC or wing prior tot he dive.
B. not breathing off your reg (at all) prior to the dive. Check it at home or at the shop prior to the dive. If it worked then it will still work now and a further check just before the dive will just supercool the regulator, which afterall does not exhcange heat well in air. Basically, you want to wait until the first stage is under water before breathing off the first stage, filling your BC or inflating your drysuit.
C. Inhaling and inflating either the BC/wing or your drysuit at the same time during the dive. The extra flow causes additional cooling in the same fixed amount of time and can lead to ice formation.
D. Pull back any hose protectors to expose the metal hose end fittings to the water. The extra exposed area helps promote heat transfer. This includes any rubber trim boots over the second stage hose inlet fitting as well.
E. Using low pressure tanks helps as the lower pressure results in less adibatic cooling.
Unless your equipment and your air tank is colder before the second dive, the chance of a freeze flow is no greater on the second dive than the first.
In cases where wear may be the cause of the freeflow, you may be slightly more likely to notice the problem on the next dive as the problem will if anything be slightly worse. This is true whether the next dive is the second dive of that day or the first dive of the next diving day.
1. Diver error - the reg is dropped in the water purge cover down and physics does the rest. On regs with an adjustable flow vane/venturi assist, setting the switch to "min" should creqate enough back pressure to stop it on it's own. With the switch in "max" it won't stop until yopu put your thumb over the mouthpiece to block the flow.
2. Excessive intermediate pressure. This type of freeflow is generally slight (at least in the early stages) and can be observed as a very slight hissing sound a few seconds to a few minutes after your reg is pressurized. It's caused by a leaking high pressure seat and if the reg is left pressurized while no one breathes off it, the leak will cause the intermedate pressure to slowly increase until the excess pressure vents though one of the second stages. In severe cases, the freeflow will be noticed under water as the intermediate pressure will incease enough in the few seconds between breaths to cause a freeflow. The condition is always progressive and that point, it is about to get bad enough to continuously freeflow.
3. A leaking second stage seat - This can be the result of improper adjustment either initally or in the form of the tech failing to properly anticipate the normal development of a seating groove. It can also be the result of the seat wearing over time. If the reg was recently serviced, it's probably the former and if it has been a year or so, it's probably the latter. In either case, you need take it in for adjustment or service.
If you have a second stage with an adjustable inhalation effort effort, you can solve the problem, at least temporarily, by turning the knob in slightly farther. It it is due to wear of the seat, you will eventually run out of adjustment and will need to take it in for service.
This freeflow differs from number 2 in that it will occur immediately upon pressurizing the reg with no delay.
4. A cold water induced "freeze flow" - This most often results from the first stage freezing up due to the cooling effect that occurs in the first stage as the high pressure air flowing through it absorbs the heat needed for it to expand. Cold water kits, usually in the form of either sealed diaphragms, oil or silicone filled ambient chambers or anti-stick or insulating coatings on key parts, help significnatly but are not always bullet proof.
Good cold water technique is a good idea if you are diving water colder than about 50 degrees. This includes:
A. not using your power inflator to fill your BC or wing prior tot he dive.
B. not breathing off your reg (at all) prior to the dive. Check it at home or at the shop prior to the dive. If it worked then it will still work now and a further check just before the dive will just supercool the regulator, which afterall does not exhcange heat well in air. Basically, you want to wait until the first stage is under water before breathing off the first stage, filling your BC or inflating your drysuit.
C. Inhaling and inflating either the BC/wing or your drysuit at the same time during the dive. The extra flow causes additional cooling in the same fixed amount of time and can lead to ice formation.
D. Pull back any hose protectors to expose the metal hose end fittings to the water. The extra exposed area helps promote heat transfer. This includes any rubber trim boots over the second stage hose inlet fitting as well.
E. Using low pressure tanks helps as the lower pressure results in less adibatic cooling.
Unless your equipment and your air tank is colder before the second dive, the chance of a freeze flow is no greater on the second dive than the first.
In cases where wear may be the cause of the freeflow, you may be slightly more likely to notice the problem on the next dive as the problem will if anything be slightly worse. This is true whether the next dive is the second dive of that day or the first dive of the next diving day.
Manta Aria
Contributor
- Messages
- 182
- Reaction score
- 1
- # of dives
- 50 - 99
So, theoretically, any service tech who's qualified can tune nearly any 1st. and 2nd stage to reduce the possibility of a freeflow? How does one handle a 1st stage freeflow? Wow, Gary D. and MixDiver have just given me research project as well as some insights! Thanx Guys : D!!!
-Manta
-Manta
I had a Mares Proton Ice octo free flow when the regulator became loose on the hose. I saw my octo was hanging on the necklace mouthpice up. When I rotated the reg mouthpiece down, that was enough to loosen the fitting. It went into FF.
I couldn't tighten it enough by hand underwater to stop the free flow - went OOA at 70 feet in a minute or so. (After that started paying more attention to rock bottom calculations.)
On the boat a wrench solved the problem.
I couldn't tighten it enough by hand underwater to stop the free flow - went OOA at 70 feet in a minute or so. (After that started paying more attention to rock bottom calculations.)
On the boat a wrench solved the problem.
OP
Thanks for the answers everyone. I dive a scubapro mk25 which is piston reg. Maybe I should consider getting it environmentally sealed.
Similar threads
