TimG

I installed my first Leak Sentinel vacuum valve, a V3, in my Subal ND800 housing in 2014. Over 700 dives, changes of camera housing and upgrades to the Sentinel system, I’ve moved through V4, V5 and now the newly available V6. As the slogan goes, I’d never leave home without it. Why? The Sentinel provides a unique extra level of security and reassurance to an underwater camera and has saved me from my own stupidity a couple of times…… So what is it? The Leak Sentinel is a small valve which screws into a spare bulkhead on an underwater camera housing to monitor for leaks even before the housing goes into water. A small hand-pump of the type used in the Vacuvin wine bottle corks then draws the air through the valve and out of the housing. (A small battery-operated pump is also available). This creates a vacuum indicated on the Sentinel by a green, “Good to Go”, blinking LED light. If the housing has not sealed properly because of a fault or, more likely user-error, the valve warning light will flash green/red or red indicating a problem. Vacuum valves are great devices particularly to help avoid user-errors and, more importantly, warn of an issue before the housing gets wet. It is this feature which makes them even more valuable than a housing leak detector which only works when water is already in the housing. Given the cost of the housing and its contents, installing one of these handy leak warning devices is money extremely well spent. I would argue it is one of the two best investments I’ve made in my system. (the other being a 45-degree viewfinder!) The Leak Sentinel system is simple to install. The valve is screwed into an empty bulkhead on the housing so that the blinking warning light is visible when diving. In earlier models (V1 to V4) the battery was part of the Sentinel’s valve assembly. In the V5 “XB” model the battery was fitted on a printed circuit board fitted inside the housing with a wire connection to the valve. This avoided the need to disassemble the valve to change battery. The V6 has just been released. Like the V5, the battery fits inside the housing. However, the cable is now fitted permanently to the battery circuit board and a connector has been added (see photo) linking the battery to the valve assembly. This is a big improvement as removing the V5 required disconnecting the wires at the printed circuit board – which could be problematic. In addition, gone is the square of Velcro which was supplied to hold the printed circuit board to the top of the housing. Now there’s a magnet! This should make battery changes even easier. Like the V4 and V5, once a vacuum is established and the LED stays green for a reasonable length of time (I usually wait an hour), the Sentinel can be switched off by pressing the LED and left until dive time. This saves battery life. Switch it back on pre-dive and the green, Good-To-Go LED should reappear and blink steadily. The Sentinel electronics allow for an element of temperature variation. It will cope for example if the camera is setup in the housing in an air-conditioned room – and then moved into a higher ambient temperature before diving. The system uses an easily available and inexpensive CR2032 battery. Battery life is certainly into the dozens of dives and many hours. On the very rare occasion when I’ve had a question, the Leak Sentinel’s producer, Miso Milivojevic of Vividhousings, has being unfailingly helpful at finding a solution in response to my emails. So, easy to install, easy to maintain and relatively inexpensive…. is it worth installing one on your system? No question. Who doesn’t want to reduce the risks of a flood and enjoy the additional reassurance a vacuum valve provides. Never leave home without one.