2nd stage Apeks ATX40 fine tuning

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Jordi

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Hi guys. I use an Apeks ATX40 with a DS4 on my stage cylinder and diving in cold water (16 deg C down to 2 in the Swedish winter). Last winter the second stage freeflowed often and this disappeared when water temperature became higher. I swapped the second stage for another one and decided to service the regulator myself with original Apeks o-rings and seat. Tested it again the last couple of weekends (water temps 10 degC) and no free flow. Unfortunately the air flow when inspiring does not stop at the end of inspiration and there is extra air coming in (and being wasted) with every breath. Somehow the sealing after air flow is not tight enough.

Adjusting the pressure on the rubber seat (by screwing in the seat) does not correct for that which leads me to believe that the problem is in the metal spring or in the 2mm o-ring that seals the shuttle valve to the counterbalance cylinder. Putting more grease on the o-ring does not help either. I have not been able to test the spring but I am now considering about replacing it if it could be the source of the problems. Any wise thoughts? Best regards
Jordi
 

axxel57

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Hi guys. I use an Apeks ATX40 with a DS4 on my stage cylinder and diving in cold water (16 deg C down to 2 in the Swedish winter). Last winter the second stage freeflowed often and this disappeared when water temperature became higher. I swapped the second stage for another one and decided to service the regulator myself with original Apeks o-rings and seat. Tested it again the last couple of weekends (water temps 10 degC) and no free flow. Unfortunately the air flow when inspiring does not stop at the end of inspiration and there is extra air coming in (and being wasted) with every breath. Somehow the sealing after air flow is not tight enough.

Adjusting the pressure on the rubber seat (by screwing in the seat) does not correct for that which leads me to believe that the problem is in the metal spring or in the 2mm o-ring that seals the shuttle valve to the counterbalance cylinder. Putting more grease on the o-ring does not help either. I have not been able to test the spring but I am now considering about replacing it if it could be the source of the problems. Any wise thoughts? Best regards
Jordi
Check the lever position after you have tighten the hose on the 2nd. ATX40 2nds are prone to dislocation of the barrel and lever, so the lever is not completely parallel with the rim touching slightly the housing of the barrel leading to a short ot longer Free Flow of the 2nd..........
 

Jordi

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Check the lever position after you have tighten the hose on the 2nd. ATX40 2nds are prone to dislocation of the barrel and lever, so the lever is not completely parallel with the rim touching slightly the housing of the barrel leading to a short ot longer Free Flow of the 2nd..........
Thank you Axxel57. It was in position but the lever was not completely parallel because there is some wiggle room for the barrel. I will test it again this week.
 

Dsix36

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This may be too basic and simple, but have you verified there is no IP creep after letting it flow a bit?
 

Bald Wookie

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Where does your IP sit on your first stage?
From what I remember, the ATX40 does not have a "dial in" knob, so there is no user adjustability when you get in the water. I believe this can be added, which I do recommend. Leave it dialed all the way out at the beginning of the dive, and as you feel a small leak by (Assuming balanced 1st stage) you can dial it in. Especially helpful in cold water where this is more prone to occur
I agree with the lever position.
 

Centrals

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I always check the IP first when my Apeks 2nd stage started to free flow slightly.
It is easy to blame the rubber seat of the 2nd stage.

The slight wriggle of the barrel is the weak link of Apeks 2nd stage but it has never caused any unwanted free flow for me.
You might have a cracked/damaged crown seat in your 2nd stage. Use a small magnifying glass to check.

Good luck.
 
https://www.shearwater.com/products/teric/

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