APEKS tek3 creep

[LanceRiley]

hi all,

Ive overhauled the left post of my tek3 with no incident. I usually leave the reg pressurized in an hour. And after that. Locks up pretty good at 9.4 bar


Dived it a few times and its perfect.

Now on the right post it has a weird creep.

Already pressurized it for hours. 30mins, 1hr and 1.5hr
Purged the 2nd stage 100 times or more to initiate a cycle



Last test. ip 9.38bar after 1.5 hrs 9.68 bar. I havent tested more than 1.5 hrs but is this acceptable?

Thats 136 psi and after 1.5hrs its 140 psi

Shouldnt it lockup? Like not move?

This is done with the inhalation knob fully opened.

Tried the inhalation knob fully closed locks up at 9.52 bar or 138psi. But need to redo this test

2nd stage xtx50 is tuned to 1.1-1.2


2nd stage was tuned with lever level to rim case. Then adjusted to free flow… tuned back to stop free low and maybe 1/12 turn more

I cant make it free flow with purge botton but breathes very well

So is this ok?

 

[lexvil]

Are you talking about the first stage or the second? The 136 to 140 over an hour isn’t something I would worry about but it should lock up so maybe longer testing is called for. The second part about the second stage is easy to test, switch second stages and see if it has any effect.

 

[Wibble]

Tec3 IP creep is common. Sometimes rubbing the seat with a pencil rubber (eraser?) may clean and cure it.

Alas the cost of a replacement body is the same price as a new reg, circa $500

If only there was a little back yard industry where they could re-ream the seats for a fee.

 

[Mobulai]

I cant make it free flow with purge botton but breathes very well

Lever hight drop might be a concern here, back up the orifice to max lever height and use the microadjust to manage the freeflow

 

[LanceRiley]

Lever hight drop might be a concern here, back up the orifice to max lever height and use the microadjust to manage the freeflow

Max lever height? How high is that?

 

[LanceRiley]

How high is that if were using the rim level as basis

 

[Mobulai]

Max lever height? How high is that?

As high as it can go — I don’t have an xtx to say with confidences but the procedure is standard for any reg

Basically, remove the diaphragm; have ithe reg horizontal (lever up); tune the orifice in till the lever starts to drop by gravity, once it start to drop back the orifice out about 1/12 (not 1/2) turn; don’t move the orifice in more than that
Now you can start adjusting from the knob side (micro adjustment, under the knob cap)

Edit: just checked an old ATX, seems max lever is at just 1-2mm above case rim

 

[LanceRiley]

Oh… so its not case level. I had the lever level to the case.

So i should let the lever rise by adjusting the orifice…. Let it rise until it starts to drop?

When i attach the lp hose to the reg and it hisses? Adjust orifice side? Or proceed to the knob adjustment?


I was taught to level the lever to the case and saw a few manuals that had that. when pressurize, adjust orifice side, adjust wob on knob side

 

[Mobulai]

Oh… so its not case level. I had the lever level to the case.

So i should let the lever rise by adjusting the orifice…. Let it rise until it starts to drop?

When i attach the lp hose to the reg and it hisses? Adjust orifice side? Or proceed to the knob adjustment?


I was taught to level the lever to the case and saw a few manuals that had that. when pressurize, adjust orifice side, adjust wob on knob side

Well it’s not wrong, just not the full information
Both sides influence the WoB, but the orifice side also affects the lever height

The manuals base on theory but don’t explain the why, and that is the part that counts — manuals also assume parts are in pristine condition (orifice, spring tension..) and seal as they are designed

Get the max height you can, then ever so slightly tighten (lever drops ever so slightly — ideally not due to lever ratio) to get a light seal (that’s perfect conditions); if it’s still hissing then adjust the knob side to avoid lever drop (which has serious consequences, the simplest is the purge button not engaging/doing anything)

Start from the micro adjustment to keep full/most usable range of the knob

 

[Mobulai]

More „theory“ in here — I’d recommend checking these threads put

Failure to freeflow after a brisk purge can be a function of two factors only: 1) the venturi-induced vacuum in the reg body with brisk airflow, and 2) the degree of valve opening, which is a function of lever height. In turn, the degree of valve opening affects #1 the amount of venturi vacuum generated.

So, if you are not getting freeflow, my first question is whether or not the mouthpiece has been removed at your test bench. The Apeks service manual specifies in a NOTE box to perform bench tests before installing the mouthpiece. Some brands (notably some Scubapro regs) have a mouthpiece restriction which will markedly decrease the degree to which their reg reverts to freeflow. The restriction doesn't affect normal (or even heavy) breathing, but serves to decrease the flow-induced vacuum. Once you have removed the mouthpiece, and your test reveals no freeflow on purge, you know you do not have enough flow to "suck" the diaphragm in.

The next issue is cracking effort. Make sure your reg has a low cracking effort (e.g., 1.0" for the XTX). Although you can get it lower, the problems of case geometry fault are a subject for another thread. If you don't have a magnehelic gauge, fill your sink with water and pressurize your reg. Lower it into the water with the diaphragm horizontal (parallel to the water surface). The diaphragm is roughly at the seam between the case and faceplate. The reg should begin to hiss lightly when the seam is 1.0" below the water's surface, and certainly before the mouthpiece goes under the water. Adjust the microadjust so that you have a light cracking effort. The reason cracking effort plays a role is that the vacuum created by rapid outrush of air from the mouthpiece may not be sufficient to keep the diaphragm pulled in if your valve requires 1.5" or 2" of opening effort. The vacuum has to counteract a larger spring force if cracking effort is set too high.

If you still don't have freeflow with cracking effort at the low end of specification, the lever height is the likely culprit. With the reg pressurized, does the reg "rattle" when you shake it? That's likely a low lever flapping against the diaphragm. If you can't hear a rattle, unscrew the case faceplate, and with the reg pressurized, LIGHTLY depress the diaphragm. Can you feel when it engages the lever? How far does the diaphragm depress before flow is initiated? If it's more than 1/16", your lever is probably too low. Unscrew the orifice in 1/12 turn increments until the lever rises a bit. If the reg begins to freeflow when you unscrew the orifice a touch, try screwing in the microadjust to increase spring tension. That dynamic interplay between the orifice and poppet spring tension is the key to all this. You can have your orifice way in, with the microadjust way out, and cracking effort will be fine, but the lever is low. You can have your orifice way out (just short of leak) and the microadjust in, and cracking effort will be fine, but the lever is too high when you try to screw down the faceplate.

The lever adjust tool is designed to put you in the ballpark between those two extremes, but as I suggested earlier, I don't bother using it. The 2008 service manual doesn't even mention it, but instead specifies screwing in the orifice, and then unscrewing until the lever rises even with the case rim. The key is lever position relative to the diaphragm when the reg is pressurized. Check that before you screw down the faceplate. PM me if you'd like to discuss offline. Good luck!

Concur, if you use the orifice to set lever height as many manufacturer's manuals suggest. Thank goodness the Scubapro G250 is not one of those (and alas, the Aqualung Legend is). In the good old G250, the lever height is preset or bent to position, and not dropped intentionally by the orifice beyond the designed seal point. At full lever height, then, the G250 poppet should not move more than a miniscule amount when the adjustment knob is screwed in. That, I presume, is why one of our OP's regs wouldn't stop freeflowing despite adding all that spring pressure.

But, halo, a point well taken. Spring pressure is a significant component for many second stages. And actually, we're splitting hairs here. I'll bet that even a correctly set G250 orifice will allow .05mm of poppet shift when the adjustment knob is screwed in enough to make the lever tight against the lugs.