Piston vs. Balanced Diaphragm

[JD.Gattis]

Wich is the best to get? and why.

 

[MechDiver]

Wich is the best to get? and why.

There is no best. They each do a job, and each does it well.
There are also hundreds of posts here already on the pros and cons of each that you can access using the search button.

MD

 

[Quarrior]

Wich is the best to get? and why.

Really depends on the diving environment you intend to dive in.

Pistons are open to the elements and prone freeze up in cold water, below 45F.

Diaphram regs tend to be environmentally sealed (not all are mind you) and tend to work better in cold water for that reason.

As for which works better. Everyone has their own belief. Some say piston is better because it has direct access to the water pressure and therefore adjusts more accurately. Others say that is a load of bunk.

Personally, I dive an environmentally sealed diaphram because I dive in cold murky water.

 

[scubapro50]

warm water diving a piston is great .... take a look at he classic Scubapro MK5 ... it's one of the most enduring designs ever. A piston just seems to hold up better than a diaphram because there are a lot less parts to wearout or break. I own a MK10 and love it. My wife has a Dacor Pacer 360 and have had the first stage worked on twice due to problems in last 4 years. That's one reason I hate to see Dacor drop their "lifetime warranty" support of it (see thread "dumped on by diving companies again".

 

[Gary D.]

Really depends on the diving environment you intend to dive in.

Pistons are open to the elements and prone freeze up in cold water, below 45F.

Diaphram regs tend to be environmentally sealed (not all are mind you) and tend to work better in cold water for that reason.

Not all in either case you just stated.

I also dive a lot of nasty water and that is one of the reasons I dive a dry bleed piston.

Gary D.

 

[Randy43068]

I have an older Conshelf SE2 but don't know if it's a piston or diaphram. Do you know which it is?

Thanks,

Randy

Really depends on the diving environment you intend to dive in.

Pistons are open to the elements and prone freeze up in cold water, below 45F.

Diaphram regs tend to be environmentally sealed (not all are mind you) and tend to work better in cold water for that reason.

As for which works better. Everyone has their own belief. Some say piston is better because it has direct access to the water pressure and therefore adjusts more accurately. Others say that is a load of bunk.

Personally, I dive an environmentally sealed diaphram because I dive in cold murky water.

 

[Quarrior]

I have an older Conshelf SE2 but don't know if it's a piston or diaphram. Do you know which it is?

Thanks,

Randy

To my knowledge and there are more knowledgeable people than me here. The easiest way to tell is to look at the first stage. If it has holes in the sides, other than the ports, it is a piston reg.

 

[garyfotodiver]

I have an older Conshelf SE2 but don't know if it's a piston or diaphram. Do you know which it is?

Thanks,

Randy

Conshelfs are diaphragm 1st stages. I own own three, one from 1969, 1980, and 1995. All very similar.

 

[Greg Barlow]

A balanced diaphragm reg cannot provide the massive gas flow that a large bore balanced piston can provide. The air passages are just too small in comparison to the orifice found in a balanced piston. That being said...A second stage can only deliver so much gas, and the top diaprhragm designs on the market can easily meet the needs of two divers at depths in excess of 150'. How many times do you need more gas than that?

Personally, I own diaphragm, unbalanced piston, and balanced piston designs. I tend to use the diaphragm varities for almost all my dives due to the bulk of my dives being in colder water.

Greg

 

[rescuediver009]

Please tell me that you did a search on this.....
I am not a veteran but I have seen 3 separate threads posting the exact same question.

No one is bette than the other though. You have to also realize that there are separate types of each:
Pistons: unbalanced, balanced sealed, balance flow through, and flow through.
Diaphragm: Balanced, Overbalanced, unbalanced upstream.

Each performs differently and one better in separate conditions. And truth be told with a blindfold on sometimes you cannot even tell the difference. I think that pistons are (not better) more common to recreational divers as they usually have a lower cracking pressure and this is more pleasant to learn to breath on. Diaphragm regs are more popular in technical diving than they are in rec diving. They can hold up to a litle more, have alot less o-rings and moving parts.

AS ALWAYS THOUGH THERE ARE EXCEPTIONS TO EVERY RULE.