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SI TECH Exhaust Valves are very sensitive to small variations in the difference between internal and
external pressure. The Exhaust Valve is adjustable between 10-200 mm column of water (1/2 to 8
inches) to provide buoyancy variation with the inherent gas volume.
Easy adjustment of the gas volume in the drysuit is hereby simplified and the drysuit may
be used as the only method of buoyancy control during normal diving conditions (BCD emptied
of gas during the dive). This will also support a controlled ascent, approx. 10-18 meters/minute
(35-60 feet/minute), provided the diver’s buoyancy is correctly compensated and the valve is set
properly.
Set the Exhaust Valve for automatic buoyancy control
You can remain neutrally buoyant without manual deflation; when the Exhaust Valve is correctly
located (on the highest point of the drysuit, most commonly on the left upper arm) and
properly set, and when you are correctly compensated with weights. When you adjust the
setting by turning the valve cover, a clicking sound will help you determine the fine tuning.
When the valve is properly set you will be able to fine tune the gas volume in the drysuit
further by rolling the body or by raising or lowering the elbow.
The valve may need further fine tuning during the dive depending on gas consumption during dive
and the suit material. There should be no gas in your BCD during the dive. The BCD is used only
as a back-up. Adjust the valve slightly by turning the valve cover. The clicking sound that
can be heard when you turn the valve cover makes it easy for you to fine tune the valve while diving.
The s and – above the logo label on the lid indicates the effect.
For reduced buoyancy
(red):
adjust counter clockwise (towards-)
= lower pressure = less gas
retained in the suit.
For increased buoyancy
(blue):
adjust clockwise ()
= higher pressure in the suit
compared to ambient water
pressure = more gas retained in the suit.
Manual deflation
If the pressure setting of the valve
is high (clockwise, to +), press any-
where on the valve lid to override
this setting and to deflate gas. How-
ever, the valve is normally operated
by minor pressure changes.
Factors that need to be considered if the deflation capacity of the Exhaust Valve seems
inadequate are:
the valve location on the suit, the suit fit (too much volume above the shoulders
could lead to a pocket of gas being trapped above the valve), the permeability of the underwear and
insufficient weight compensation.
For further information, please contact your local SI TECH dealer!
