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> From: "Richard Hayward" <hddiver@ic*.ne*>
> To: "techdiver" <techdiver@aquanaut.com>
> Subject: Cold water performance of Scuba Pro Regs
> Date: Sat, 14 Feb 1998 21:23:45 -0800
> My question is, is this typical of Scuba Pro regulators to perform
> poorly in cold water. My friend has seen many Scuba Pro regulators free flow
> on his charter boat in Whitefish Bay Lake Superior, but I do not think that
> they had this new TIS thermal insulation system on them. Does anyone else
> out there have any experience with any Scuba Pro reg in water of this
> temperature (32 degrees Fahrenheit 0 degrees Celsius)?
Richard,
Piston regulators generally freeze in one of two ways. The
more common way is for ice to form around the piston and spring which
prevents the piston from moving and closing on the seat. The TIS is
a washer assembly that is designed to insulate the spring from the
piston and keep the cold from transferring from the piston to the
spring. If the cold is not transferred theoretically ice will not form
on the spring. This however doesn't keep ice from forming around the
piston, and the regulator can still freeze up.
By using an antifreeze kit, the piston and spring are
encapsulated in silicone grease that will not freeze. If no ice can
form around the piston and spring, the regulator should not be able
to freeze open. I have never, nor have any of my customers that I
am aware of, had a scubapro 1st stage freeze with a grease kit on it
freeze up. Unfortunately the TIS washer has not been as effective
without the grease kit.
I have never seen any performance difference with the grease kit,
and doubt that there would be any since the water pressure will
travel through the grease and keep the piston balanced at depth.
The second way that a regulator freezes has to due with moist air
in the tank. If the air in the tank isn't really dry (a dew point
below say -60 degrees) the moisture in the air will collect on a part
and freeze into ice as it is in the cold stream of air coming from
the tank. This is generally more common in the second stage valve
system. When you have formed enough ice, the valve will not close and
the regulator free flows.
My advice: Put a grease kit on your MK10 and make sure it is
completely filled with grease. Check the air analysis where you get
your tanks filled. If the dew point isn't at least -50 degrees, find
some drier air. NOTE: portable compressor generally lack the
filtration to get this low a dew point, and can often be the cause of
freeze up. Lastly, there will be no difference between a MK10 and an
MK20 with regard to freeze up. If you don't put a grease kit on an
MK20 it will freeze just like you MK10.
Hope this answers your question!
Ted
P.S. I have been a Scubapro authorized technician for 20 years, and
have more than 50 dives in fresh water below 35 degrees. This
information is from first hand experience.
>
> Would an antifreeze kit reduce the performance of the first stage and
> would it help with the cold water? It is to my understanding that when the
> ports to the ambient chamber are covered by an antifreeze kit that the
> performance is reduced. If this is true how much?
>
> I know a piston reg will deliver more air than a diaphragm regulator on
> any day, but that does me no good if the regulator is going to free flow at
> the sight of snow.
>
> I really like the design of the G250 and D400 and am seriously
> considering purchasing two of them, however I want to make sure that these
> regs are not going to blow off every time I get into cold water, which
> around here is 9 months of the year (12 months if you go past 100 feet).
>
> Can anyone out there give me any suggestions, anyone have any experience
> with these regs in water this cold? I know they are good regs, I just want
> them to be good cold water regulators as well. Any Scuba Pro technicians out
> there with cold water experience?
>
> Thanks for your time
>
> Richard Hayward
>
>
>
>
>
>
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