Scuba Diving Regulators FAQ

1. What is a regulator?

In scuba diving a regulator is an essential piece of equipment that regulates the pressurized air from the tank and converts is into breathable air.  Air tanks store air in a high pressure situation and this means you cannot breathe straight from the tank.  The regulator connects to the tank and reduces the pressure of the air so that it is safe to breathe.  You cannot breathe underwater without a regulator so this is a vital piece of scuba diving kit that needs to be maintained and serviced to keep it in top condition.

2. What is an alternate air source?

An alternate air source is an additional second stage regulator (mouthpiece) which provides a means for a second person to breathe air from your scuba cylinder supply. This is used in situations where a divers regulator may have failed, allowing that diver to share the air carried in his buddy’s cylinder.

3. What is the difference between first and second stage regulators?

The first stage of the regulator is the part of the regulator that attaches directly to the cylinder, this reduces the pressure of the air from the cylinder down to an intermediate pressure held in the hose which connects to the second stage of the regulator, the second stage of the regulator sometimes called the demand valve is the part of the regulator that the diver holds in the mouth and breathes through. This second stage reduces the intermediate pressure of the air in the hose to the ambient pressure to the depth of the sea water the diver is in.

4. Do I need a balanced regulator?

Generally most scuba instructors and anyone in the industry would advise their students to purchase a balanced diaphragm regulator. This gives the greatest scope to develop their skills without outgrowing the capabilities of their regulator. A balanced regulator is designed to make it easier to breathe at any depth.  The deeper you dive the more pressure the air in your tank will be put under.  This makes it much harder to draw the air from the tank. Divers without a balanced regulator will notice that the deeper they dive the more breathing resistance they will encounter.  A balanced regulator will ensure that the diver can still breathe easily from their air supply regardless of depth.  You will need a balanced regulator if you intend do dive deeper than 100 feet on a recreational or technical dive.  Balanced regulators are typically more expensive than unbalanced versions because the design is more complex.

5. What exactly is the yoke?

The yoke, sometimes called the A clamp and also called the international fitting, is the means by which the first stage is secured to the cylinder valve. The yoke fitting is a metal oval that goes over the tank valve and holds the regulator in place and allows air to pass into the low pressure hose.

6.  What is the difference between DIN and yoke regulators?

DIN and Yoke are both means of securing the first stage to the compatible cylinder valve, though are generally not interchangeable without using a converter.  The main difference is in how the two regulators attach to the tank. The DIN regulator screws into the tank valve directly whilst the yoke regulator fits over the top and clamps into place with a tightening screw.  Technical divers prefer the DIN system as it offers a superior fit and will handle higher pressure than the yoke valves and also has a lower probability of an O ring rupture and losing air. 

7. Should I use a yoke or DIN regulator?

The type of regulator you choose is a personal choice and will depend on which tanks you are using and your style of diving.  Yoke valves are standard for most recreational warm water diving so if you are hiring equipment you will most likely get this type of regulator.  However if you are going to be carrying out technical diving or using high pressure tanks it is a good idea to use DIN regulators as they offer higher performance.  A service technician will also be able to convert yoke systems to DIN and vice-versa and you can also buy adaptor kits so that you can get the best of both worlds. Generally, if divers are intending to holiday around the world and dive while they travel the international fitting or the yoke clamp is by far the more common fitting divers will encounter.

8.  Is there any way to stop jaw fatigue?

Divers expect to get some jaw fatigue after a dive but if this is a big problem for you then there are some areas to look at.  Firstly check your regulator mouthpiece.  If you have to grip this too tightly between your teeth then you will exacerbate jaw fatigue.  Try a few different mouthpiece designs until you find one that you can hold comfortably between your teeth without biting down too hard. Silicone mouthpieces can be more pliable and many divers find these are easier to use than rubber mouthpieces. Also the addition of swivels and elbow joints where the low pressure hose enters the mouth piece can reduce the need to grip the mouthpiece so tightly.

Another common problem is that the low pressure hose attached to the regulator can pull the mouthpiece to one side as you turn your head.  This means you have to grip the mouthpiece tightly to keep it in place and this can cause jaw fatigue.  You can help to prevent this by using a swivel joint hose adaptor.  This has a ball joint style design that allows the hose to rotate easily which stops if from pulling as you turn your head.  Swivel joint designs also make it easier to share air as you will be able to turn the mouthpiece to face the diver in need of air without pulling or twisting the hose.

9. What part of regulator kit is the first stage body?

This is the heavy metal part of the regulator that attaches directly to the cylinder valve. From which the hose is run towards the second stages and houses the mechanism that converts high pressure air straight out of the air tank into intermediary pressure.  It is connected to the tank using low pressure hoses.

10.  Do I need to replace the dust cap if I lose it?

The dust cap is actually a very important piece of kit.  It is essential that no water enters the first stage body on your regulator gear.  When the first stage body is not connected to the tank it is possible for water to seep into the opening that connects the body to the air tank valve.  A dust cap is a simple rubber cap that fits over this opening and seals it to prevent any water from seeping in.