A leaky regulator is more than just annoying. It is generally the sign of a potentially serious problem requiring immediate attention. Here are common sources of regulator leaks and how to deal with them.
1 First stage leaking
Where: From orifices, holes, and seams in the first stage housing.
Looks like: Either an occasional bubble, a constant small stream, a lot of bubbles or a large stream.
The problem: Wear and tear, perforated diaphragm, broken piston O-ring, worn seat or mis-adjustment of the internal parts during maintenance.
The fix: This requires a certified technician. It involves working with high pressure (3,000 psi) and is very dangerous. If you don’t know what you are doing, it can cause serious bodily harm.
Abort the dive? This is a judgment call. It’s not likely to worsen quickly, and an occasional bubble might be tolerable for the day. If the leakage increases, however, head for the surface.
2 First stage bleed
Where: This will come from a single orifice on the first stage (a small hole, usually with a rubber insert).
Looks like: A steady stream of very tiny bubbles or small bubbles leaking at a somewhat constant rate.
The problem: There is no problem. The bleed is intentional, a design feature of the dry piston-type first stage. Again, this is designed to happen.
The fix:: There is no problem, so there is no fix
Abort the dive? There is nothing wrong. The air loss is minuscule. You will lose less than one breath every 60 minutes.
3 First stage yoke leak
Where: This occurs between the tank valve and the high-pressure valve seat at the yoke.
Looks like: An occasional bubble to a constant stream.
Sounds like: Bubbling from a soft drink to a boiling pot of water.
The problem: There could be several causes for this. The O-rings could be dirty, cracked, worn, dry or the wrong size. The seat is damaged or dirty with sand or salt. The yoke is loose or not positioned correctly in the eye of the tank valve. If you are using a DIN-to-yoke adapter, make sure the alignment on the connection point is correct because some adapters make the alignment of the yoke difficult.
The fix:: Remove the O-ring, clean and inspect the seat. Replace the O-ring with a new one, coated with just enough silicone to make it supple, not greasy. Tighten the yoke firmly but don’t force it. No luck? Try a different tank.
Abort the dive? This is a judgment call if the leak is very small. Generally speaking, you should return to the surface and replace the O-ring.
4 Tank O-ring leak
Where: This occurs between the tank valve and the high-pressure valve seat at the regulator yoke.
Looks like: Divers hide behind each other or look at you like you are an idiot.
Sounds like: Your tank is about to explode and the world is about to end.
The problem: This typically happens when a diver first opens the tank valve. If the seat is loose, pressure forces the O-ring to squeeze through the gap and tear. The escaping air can be deafeningly loud. This can also happen if you use the wrong-size O-ring in your tank valve.
The fix:: A new O-ring and a firmer grip on the yoke screw; however, keep in mind the yoke screw (or DIN handwheel) should only be finger tight. Do not tighten your regulator.
Abort the dive? If you are underwater when this happens, you must quickly abort the dive. Make sure you maintain the correct ascent rate. Usually, this happens on the surface when divers are gearing up and getting ready to dive, so you are free to do your dive once your heart rate comes back down.
5 Hose O-ring leak
Where: This happens at either the crimped end of any hose, between the hose end fitting and whatever it screws into (first stage, second stage, BC inflator, SPG, etc.).
Looks like: This will be isolated, ranging from slowly formed bubbles to a constant bubble stream.
Sounds like: No sound is typical, or you can hear a very low hiss.
The problem: O-ring is dirty, cracked, worn, etc. A leak immediately after a service usually means the tech has not tightened the hose enough. If you removed the hose and reinstalled it, you didn’t tighten the hose.
The fix: Where there is a swivel on the hose, separate the components between the swivel nut and the next nut, not between the two nuts and the SPG or second stage. Do not overtighten; once it stops moving easily, just one nice little tug on a wrench will suffice.
Abort the dive? If it’s the high-pressure hose to the SPG, it will usually be a small leak. You can continue the dive if it doesn’t affect the gauge.
High-pressure hose leaks look excessively dramatic underwater, but it involves very little air — the HP orifices are tiny; on some connectors you cannot even see the HP hole. A low-pressure hose actually leaks more air, but you will still have time to return to the surface calmly and deal with it.
6 Worn hose leaking
Where: This can happen anywhere on any hose but usually near the first-stage end fitting.
Looks like: A visible bubble in the hose itself. Tiny bubbles leaking from the hose, a chain of tiny bubbles on the surface of the hose, or a steady stream of bubbles.
Sounds like: Usually no sound at all, but it could be a sizzle or fizz noise like when you open a can of Sprite or Ginger Ale.
The problem: The inner, woven layer of the hose has developed a weak area, usually through constant flexing. Air leaks to the outer, scuff-protecting layer of the hose, which has a chain of tiny relief holes along its length. That’s where the bubbles come out.
The fix:: Replace the hose. High-pressure and low-pressure hoses are not interchangeable, nor are low-pressure regulator and inflator hoses.
Abort the dive? The high-pressure hose is a judgment call, depending on how severe the leak is. We encourage you to surface to replace a low-pressure hose.
7 Second stage leaks
Where: From the second stage exhaust.
Looks like: A bubble every few seconds to a constant stream of bubbles that will not stop.
Sounds like: A slow bubble like water going down the drain in a full sink or tub to a pot at full boil.
The problem: The two most common issues are a first stage out of adjustment and delivering too much pressure, or the second stage “cracking pressure” too low
The fix:: Turn back the second stage adjustment (if you have one) for more breathing resistance until the leak stops. If you must turn it back several times during a dive, this is a sign of first-stage problems, and possible failure of the first stage is coming. Turning the minimum/maximum or venturi switch will have no effect. Have your reg serviced by a qualified professional at the first opportunity.
Abort the dive? If you can keep the leaking under control and it doesn’t annoy you to death, it is a judgment call, but if the problem remains, or is getting worse, head for the surface.
8 Second stage leaking at the valve seat
Where: From the primary or octopus’s exhaust.
Looks like: The same as the excess pressure leak we just discussed.
Sounds like: Same as the excess pressure leak.
The problem: Sand, grit, or corrosion under the second stage valve seat prevents it from sealing, or the repetitive operation has worn a groove in the seat and will not allow the valve seat to seal fully.
The fix:: Shake the second stage in the water while pushing and releasing the purge button (tank must be on). You might wash out the sand or grit this way. We do not encourage you to take your regulator apart if you are not a certified technician. There are a lot of very small, very Important parts that you could easily lose. If it’s a corroded seat or an improper adjustment, only a technician can make this repair.
Abort the dive? The fix above may reduce the leak and make it manageable. Otherwise, make a calm, normal ascent (your air is not disappearing as fast as it sounds) and keep a close eye on your SPG.
9 SPG spool leak
Where: This occurs between the swivel fitting and the body of the submersible pressure gauge, or you may see leaking from the gauge console.
Looks like: Anything from a steady stream of bubbles to a constant fizz.
Sounds like: Anything from a boiling pot of water to the space shuttle taking off.
The problem: The spool, or barrel swivel, is the hollow stud on which the swivel mechanism mounts. Banging and dragging the SPG can bend or break the spool or cut/tear its O-rings.
The fix: This requires some technical knowledge, but many dive boat captains, resort operators and dive shop folks can do it. The hardest part of this is getting the SPG out of the console. This may require a lot of swear words and force to get it out of the console and the same amount of swear words and force to get it back in once changed.
Be advised that the easiest thing to do is change the entire spool or barrel swivel, as the size of O-rings that are on these items are not easy to work with and very hard to control. If you try to change these O-rings, be ready for a lot more swear words and usually a thrown spool/barrel swivel followed by frantic searching as to where it went.
Abort the dive? It’s a high-pressure hose leak; it looks and sounds worse than it is because the pressure is high, but the volume is low. As long as the SPG is reading correctly, it is a judgment call; if you’re using an air-integrated dive computer, it’s not an issue.
A special thanks to Kary McNeal of Aquatic Ventures who authoried this article.