Apeks Heat Exchanger?

[DomRep Diving]

Ok... I saw in another post, a comparison about the differences in the AT20, ATX40, ATX50, ATX100 & ATX200. I came to the conclusion that I''m looking for something like the ATX50, but since I've read that most people never use the knob in the ATX50 and that is the only difference between the ATX40, I'll get the 40.
But, going a little bit farther, the only difference between the ATX40 and the AT20 appears to be the heat exchanger. What is it for?
I don't know if it's use depends on the temperature of the water you dive, but I guess it has something to be, so for you to know, I only dive warm water (80F year round).

Do you think I need the heat exchanger, or It will be useless for me and I can go by with a AT20?

Thanks for your help!

 

[Hallmac]

the heat exchanger is for cold water diving where freeze up is a concern. Recommended below 39 degrees. It aids prevention by using the heat from the water to warm the air flowing through a small orifice thus helping to lower the risk of freeze up.

Hallmac

 

[nickjb]

Hallmac is right, although I believe that they are recommended below 50F (10 C).

If you only dive 80F then a AT20 will suit you just fine. In theory you can buy the heat exchanger as a spare part if you later change your mind about how cold is too cold.

 

[mmakay]

The first stage of the AT20 is not environmentally sealed, where the ATX40/50 is. Again, this is a big deal in cold water, less so in warm. It does have other advantages, though. (Silt, sand, salt crystal formation, etc.)

I don't know if there are other 1st stage differances. Perhaps somebody else can shed some light.

 

[nickjb]

The AT20 refers to the second stage. It usually is matched with a US4 first stage (UnSealed, 4 LP ports).

I agree that extra sealing helps keep sand and silt out so if you can get it with a DS4 (Dry Sealed, 4 LP ports) then that is better.

Aside from the sealing these regs are identical.

 

[mmakay]

I've seen the AT20 matched with the UST more often than the US4. (Likewise I generally see the ATX40 with a DST, not DS4.) I know there are a lot of anti-turret advocates on this board, but do the two perform the same?

 

[Scubaroo]

mmakay once bubbled...
I've seen the AT20 matched with the UST more often than the US4. (Likewise I generally see the ATX40 with a DST, not DS4.) I know there are a lot of anti-turret advocates on this board, but do the two perform the same?

The UST/DST/US4/DS4 all have the same internals - they should perform the same. Actually I think all of the current Apeks regulators have the same internal design - the differences are mainly sealed versus unsealed, swivel turret or no swivel turret, and port positioning.