Low Profile Auto Dump Valve The Auto-dump valve is designed to control the volume of air in the diver\'s dry-suit and can be adjusted by the diver to attain the correct buoyancy and allow a safe ascent. Low Profile Auto Dump Valve Operation STATIC PHASE The volume of air in the dry suit is controlled by means of a rotating cap. Turning the cap clockwise increases the spring load acting on the valve seat and allows a larger volume of air to be maintained in the dry suit. Anti-clockwise rotation of the cap reduces the spring load, allowing air to escape and so hold a smaller volume of air. The rotating cap also features a ratchet mechanism, to prevent accidental adjustment of the dump valve. DUMP PHASE As the diver ascends, the air in the dry-suit expands, increasing the diver\'s buoyancy. The auto-dump valve senses the increased pressure in the dry-suit, which lifts the valve seat against the spring, allowing air to vent. This venting action maintains the volume of air in the dry-suit and allows a controlled ascent by the diver. If, at any time during the dive, it is felt that there is too much air in the dry-suit, the cap can be pressed manually to over-ride the valves settings and vent excess air. PURGE PHASE If the cap is pressed with insufficient dry-suit pressure a secondary non return valve is fitted to prevent the ingress of water into the dry-suit. Selection of under clothing is important to allow escaping gas to vent through the valve, however the back nut is designed to prevent under clothing from blocking the escaping gas. The valve can be assembled and removed from a dry-suit without the use of any tools, this is achieved by pressing the cap and turning simultaneously to lock while the back nut is removed or tightened.