Scuba Pro starts pushing too much air below 50'

[elan]

We dove with my buddy yesterday and once we submerged below 50' he started showing me the reg started bubbling we moved up 10 feet and he signaled it was ok. We made a dive at 45 ft and the reg was fine. So it was not free flowing but was pushing to much air into the mouth and at some point it did not stop until we moved up. We have measured the IP at the surface and it was 140 PSI. dropping withing 5-10 PSI when inhaling and quickly returning back. He said he felt few pieces of ice in the mouth while breathing. He will take it to the tech to check what can be a problem but if you have encountered this problem before it would be interesting to hear your comments. I know the first stage is SPMK17, I'm not sure which second stage he has exactly but it's one of the recent SP second stages. The level position was in the hardest breathing zone but at this hardest position it breathes as easy as my FHVI in the lightest position.

The reg is 8 month old and has not been serviced yet.
Thanks a lot

 

[redacted]

If it has a VIVA adjustment, the feeling of positive pressure breathing can probably be controlled by reducing the venturi effect. Some folks like PP breathing as it does reduce WOB, but other find it uncomfortable.

Otherwise, a tech should be able to reduce or eliminate that effect.

 

[ShipWreck Mike]

I have a 15+ year old G250 and MK10, I have never experenced iceing. I have taken my setup down to 110' and 250 psi left in my tank with the adjustment knob in the hardest breathing position with no problems. Do you dive in extream cold water?

 

[elan]

I believe this should not be happening. It's not extremely cold but around 39-40F

 

[cbmech2]

The IP is within the range but, it is kind of hard to say without knowing what type of second stage we are dealing with. Sounds like it may have to be detuned a bit (tension on the spring increased). You can do this a bit of you happen to have a S600 or other regulator with that sort of diver accessible adjustment. If not. you should probably take it to your LDS and have them bench check it and detune it a little bit for you.

 

[elan]

I confirmed with him today he has S600 second stage. I spoke to my LDS and they said that IP should be lowered a bit for cold water, they had similar case with MK25 but at 80' in the same place. His second stage lever was in the lowest position. He is taking it to this LDS so we will see what will happen soon. I will keep you updated.

 

[Packhorse]

Where there is ice there must be low temp and water.
Easy to see where the low temp is but where is the water coming from?