Valve related issues
The most common problem people experience is a loss of pressure. Assuming the cap is well sealed against the keg (we’ll come back to that), the three ways in which gas can escape via the S30 valve are through the gas-in path, the gas-out path, or where the valve goes through the cap.
The valve seal is achieved using a thick rubber washer that gets pinched between a flange on the valve and the cap the valve is fitted to. This seal rarely leaks and when it does, it’s usually because the joint has been over tightened and the rubber washer has been distorted. In the left-hand image below you’ll see how the rubber seal is squeezed out from under the flange and is distorted through over-tightening. In the image on the right the seal is more circular and will give a better seal (we’ll return to the cable-tie). Before fitting the valve make sure there are no burrs, no raised edges, and no imperfections around the hole in the cap (also be sure not to create deep scratches or scores where the cap will come into contact with the seal) and make sure the rubber seal itself is in good condition. When fitting the valve tighten the nut as far as you can with your fingers and then use a spanner to tighten the nut another ½ to ¾ of a turn. If you over tighten the seal don’t just back off a little, undo the nut until the rubber washer moves freely and returns fully to it’s rounded shape and start again.
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I noted above the gas-injection mechanism. You inject CO2 at the top and it enters the keg through the bottom of the valve, emerging from the hole in the side of the pin with the pink rubber tube over it. The rubber tube allows the gas in but stops it escaping again.
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The problem people sometimes get is that when injecting CO2 the pressure of the gas not only squeezes past the pink rubber but blows the pink rubber seal clean off its pin and into your beer. If this happens you now have an open route for gas to flow back out the same way it came in AND you now can’t inject any gas until you’ve fixed the problem and your rubber seal is in your beer! This latter point isn’t so much of an issue if you have a spare rubber seal but it would be better to avoid the whole sorry story. A cable-tie tightened around the pink rubber (but not blocking the gas-in hole) is the solution. See in the third image along the hole is still clearly visible throug the pink rubber tube.
One important point though, the rubber seal also must not be pushed hard against the valve flange causing it to buckle because this also causes gas leaks so if required trim
a tiny sliver from the rubber tubing.
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Also just a reminder that if, when injecting CO2, the gas seems to be going everywhere except into the keg there’s a good chance this o-ring has been stretched or damaged and is no longer sealing around the neck of the CO2 bottle. It can be replaced and just sits in a groove.
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By far the most common cause of trouble is the pressure-release rubber and it’s doubly frustrating for people because it almost always fails without any sign of failure! Huh?
The large brown rubber seal in the image below is the one that allows gas to escape when pressure exceeds a safe threshold – you’ll remember the gas escapes through the hole behind the rubber seal. What happens though if the rubber has become stretched and is not gripping tightly enough? The answer of course is that it will allow gas to escape at lower pressures, maybe no presure at all if the rubber is really slack. This is exactly what happens and is
almost always the explanation for a leak you can’t seem to trace. The perfect-looking rubber seal in the image on the left and in the middle is the same stretched rubber you can see in the image on the right (shown next to a new rubber seal for comparison). The rubber seal streches over time and looses elasticity so although it looks fine it allows all your precious CO2 escape.
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I use one of these sleeve expanders to fit the new rubber seal but it can be done with a couple of watchmakers screwdrivers or other strong & thin implements but of course be wary of nicking or piercing the rubber. When you seat the rubber seal make sure it’s centred around the groove to get the best seal.
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