Home Tech Tips Scuba Tech Tips: Balanced Regulators – Why/How?

Scuba Tech Tips: Balanced Regulators – Why/How?

Alec - Regulators

Hi guys, Alec Peirce with Tech Tips once again – here at Dan’s Dive Shop in St. Catherines, Ontario (if you get a chance in this area, make sure to drop in). Here I am with my professional screwdriver, Philips, and what I want to do for a few minutes is the ongoing controversy of balanced and unbalanced regulators. Now what you ultimately end up using depends on a lot of things.

If you’re a casual diver, you go to the Florida Keys and dive 15 or 20 feet on a nice warm reef two or three times or year, then this is not a big issue for you: you’re fine with any regulator the local dive store suggests: if it’s a standard regulator, meaning it’s not balanced, that’ll work just fine for you. If, however, you are a more enthusiastic diver and you do a lot of dive trips and go deeper, deeper than 50 or 60 feet; maybe you dive in colder water for a variety of reasons. If there’s anything to indicate your diving is beyond very basic recreational diving, your local dive store will probably advise you to have a balanced regulator. Almost all regulators beyond the very basic regulator available for manufacturers are balanced. If there’s six or seven or eight regulators in a manufacturer’s line… usually the first one, their basic sport regulator may not be balanced but the rest will be. It’s a very common feature.

What’s the difference between the two and why would you want it? I’ve explained this before that the reason to get balanced is that having a balanced regulator evens out the breathing, largely. Whether you’re diving in shallow water or deep water; whether you’re diving head up looking around or you have your head in a hole digging for treasure or taking a picture; whether it’s the beginning of the dive when your tank is full or at the end of the dive when your tank is getting low on pressure. In any differing circumstances or situations during the dive, a balanced regulator always breathes the same: smoothly and easily. With a regular regulator, unbalanced if you’d like, there may be some variations. My wife says I’m not very sensitive and I disagree – I cry at movies – but I don’t really notice much of a difference; but there is a difference. Another reason for having it balanced is that the orifice, the holes the air travels through, are bigger in amount. If a diver came into my store and he was a big diver, I wouldn’t allow him to buy an unbalanced regulator because I know at some point if he’s fighting a current and breathing heavily, he may starve a bit for air.

Let me deal with the difference. We’ve talked about why, however very few divers can adequately explain the difference between the two: how does an unbalanced or normal regular differ mechanically from a balanced regulator? I can show you. It’s very simple. I made up these two diagrams.

This top regulator is a standard regulator – not balanced. There’s a body, this black portion is the chrome brass body you shine up and keep nice and neat on the outside. There’s also a diaphragm, a rubber disk that is flexible, so it moves in and out. The diaphragm sits on a shaft that goes into the body and ends in a flexible seat, a rubber or silicone seat that seals to stop the air flow. When you breathe, the diaphragm moves back and forth, that moves the shaft back and forth, and that opens or closes the valve. In this particular configuration, not balanced, the high-pressure air comes from the tank this way and it pushes against the seat, opening it to let air through. When you breathe, air comes in; when you stop, the diaphragm moves back and air flow stops. It should be obvious the high-pressure air pushing on that seat is helping to open it: pushing it in the direction you want it to go to open. Of course, that same high-pressure air pushing it open makes it a bit hard for the diaphragm to close it. With a couple of levers and a bit of help, the diaphragm closes the valve when you’re exhaling. When you breathe again, the high-pressure air pushes on it and helps it to open. When your tank is full and there’s high-pressure air pushing on the valve at 3000psi, it’s pushing really hard. At the end of the dive, when the tank pressure is low, it’s pushing with less effort: only 500psi. Obviously, it feels different and it is easy to breathe from an unbalanced regulator when the tank is full; it’s harder to breathe from an unbalanced regulator when the tank is not full. The high-pressure is helping to open it.

Let’s look at a balanced regulator. Normally you’d get a balanced regulator to eliminate those differences between the high-pressure air helping or not helping. It’s really very simple. All they did was put this shaft that controls the valve through the high-pressure chamber. Now the high-pressure air comes from the side. If high-pressure air is coming into this chamber, it’s not pushing on the shaft: it’s not trying to close or open it. It’s just sitting around the shaft doing nothing. When you suck in, the diaphragm moves this way, the valve opens and you get air. When you exhale, the diaphragm moves back and closes the valve. The high-pressure air has nothing to do with it, whether it’s 3000 or way down to 500psi. The breathing is consistently even.

One more small thing I’ll add before I go: how do you tell between a balanced and an unbalanced regulator? The easiest way is to ask. Your local dive store, if they’re showing you different regulators, will certainly know. Or you can go to the manufacturer’s website and it’ll tell you: it may not tell you a regulator is unbalanced, but it will definitely mention it’s balanced. There’s an easy way that, in most cases, would help you to tell whether a regulator is balanced or unbalanced. With this regulator, you can see the dust cap where the tank air comes in. It fits the configuration of the diagram. The high-pressure air comes in at the end of the regulator.

There’s some very basic information that might be of interest to you. Now you may have a better understanding of how it works. It’s very simple.

That’s it. Alec Peirce Scuba with Tech Tips from Dan’s dive shop. Talk to you again soon!