Apeks XTX lever height

[buddhasummer]

Just working on my first xtx50 and that is exactly my problem right now.

Interesting, I'm diving Saturday so will get a tank tomorrow and have a more thorough look into it. I'll post back my findings.

 

[Macan]

Interesting, I'm diving Saturday so will get a tank tomorrow and have a more thorough look into it. I'll post back my findings.

Some simple tests for the XTX 200.

1. Freeflow Land Test: On land, Venturi lever set on max +, Adjusting Screw (Inhalation knob) set to max open (counterclockwise) . Cycle purge button quickly. The Reg SHOULD freeflow and stop when you set the Venturi lever to Min - or when you cover the mouthpiece with your thumb.
2. Freeflow Water Test: With the second stage fully submerged in a bucket of water, Venturi lever set on max +, Adjusting Screw (Inhalation knob) set to max open (counterclockwise), mouthpiece facing the surface. The Reg SHOULD freeflow when purged and stop freeflowing when the Venturi lever is moved to Min - .
3. Inhalation Resistance Test: Venturi lever set to Min -, Adjusting Screw (Inhalation knob) set to max closed (clockwise), you should be able to breathe from the Regulator albeit with a slight but acceptable resistance.
4. Burping/Dribble Test: Venturi lever set on max +, Adjusting Screw (Inhalation knob) set to max open (counter clockwise), a submerged second stage should not be leaking gas. The second stage SHOULD also not be burping or dribbling gas (bubbles emerging every few seconds).
5. Cracking Pressure Test: Absent a Magnehelic gauge, Venturi lever set on max +, Adjusting Screw (Inhalation knob) set to max open (counter clockwise), slowly submerge the 2nd stage mouthpiece facing up. The 2nd stage should very slightly hiss out gas when the waterline reaches the cover line (where the case cover meets the body). And increase the gas output as the 2nd stage is further submerged and finally freeflows before the waterline reaches the mouthpiece opening.

 

[rsingler]

On both method, is the 2nd stage free-flowing (as it should) when the purge is rapidly cycled and mouthpiece facing up? Using the "no tool method" (adjusting the metal seat until it hiss and backing off slightly), I find that that the 2nd stage does not free flow at all.

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!

 

[StefinSB]

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!

Awesome. Just tried it during my lunch break. All good now. Thanks!

 

[Scuba Doobie Do]

I'm paying close attention to this thread because I just bought an XTX50 and the technician who set it up didn't seem to know what cracking pressure was when I talked to him on the phone and asked if he could write down the IP/cracking pressure of my new regs. I'm not too sure he even checked the lever height, so I'll definitely be checking all of this.

 

[rsingler]

...the technician who set it up didn't seem to know what cracking pressure was when I talked to him on the phone...

Seriously, though, let's hope you were talking to a salesperson, and not to their technician. Some small shops just have one person that handles service, and everyone else knows only as much about equipment as they learned during OW training.

I'm keeping my fingers crossed for you.

 

[Couv]

PM me if you'd like to discuss offline. Good luck!

DO NOT PM and discuss this offline. Too much good info here to avoid sharing. Yes, good luck and keep us posted.
TIA

 

[Macan]

Another possible cause for the 2nd stage not free flowing (it should) is a damaged silicone seat.


If the silicone seat is damaged (by having too many "sets" i.e. imprints) due to excessive (repeated) adjustments while the system is pressurized, it will leak early giving a false indication that the lever is set too high when in fact it may be set correctly or low. This will cause the tech to think that the lever is too high (it's leaking after all) and further adjust / "close" the metal seat until the leak stops. This may set the lever too low causing it not to free flow and worse, increase the inhalation effort/cracking pressure.


This is one of the benefits of the lever height tool. It allows the tech to tune the XTX with minimal adjustments vs the risk of repeated adjustments without the tool.


Something to consider.

 

[Scuba Doobie Do]

Seriously, though, let's hope you were talking to a salesperson, and not to their technician. Some small shops just have one person that handles service, and everyone else knows only as much about equipment as they learned during OW training.

I'm keeping my fingers crossed for you

Some simple tests for the XTX 200.

1. Freeflow Land Test: On land, Venturi lever set on max +, Adjusting Screw (Inhalation knob) set to max open (counterclockwise) . Cycle purge button quickly. The Reg SHOULD freeflow and stop when you set the Venturi lever to Min - or when you cover the mouthpiece with your thumb.
2. Freeflow Water Test: With the second stage fully submerged in a bucket of water, Venturi lever set on max +, Adjusting Screw (Inhalation knob) set to max open (counterclockwise), mouthpiece facing the surface. The Reg SHOULD freeflow when purged and stop freeflowing when the Venturi lever is moved to Min - .
3. Inhalation Resistance Test: Venturi lever set to Min -, Adjusting Screw (Inhalation knob) set to max closed (clockwise), you should be able to breathe from the Regulator albeit with a slight but acceptable resistance.
4. Burping/Dribble Test: Venturi lever set on max +, Adjusting Screw (Inhalation knob) set to max open (counter clockwise), a submerged second stage should not be leaking gas. The second stage SHOULD also not be burping or dribbling gas (bubbles emerging every few seconds).
5. Cracking Pressure Test: Absent a Magnehelic gauge, Venturi lever set on max +, Adjusting Screw (Inhalation knob) set to max open (counter clockwise), slowly submerge the 2nd stage mouthpiece facing up. The 2nd stage should very slightly hiss out gas when the waterline reaches the cover line (where the case cover meets the body). And increase the gas output as the 2nd stage is further submerged and finally freeflows before the waterline reaches the mouthpiece opening.

I tried out my regulators and I'm pretty sure he just checked the IP (he said 135) and screwed in the hoses. The low pressure inflator was on the wrong hp port (would work if I dive with the environmental seal up) and I got the following results to your checklist:

1. Nope. Double nope. I couldn't get either my primary or octo to freeflow no matter what I did out of water. In fact, when I push the purge on the side instead of middle for the half purge, I get NO purge. No massive flow when holding the purge button either, fairly mild.

2. This worked fine. Both second stages would freeflow if I held the purge underwater for a second while they face up. I had to hold the purge a second though, and they would stop slowly and dribble a bit, but then stop freeflowing in a second or two.

3. No problems. Harder to breath but could still get air on demand.

4. No leaking or dribbling.

5. Primary starts to hiss air maybe halfway in. Full flow just before mouthpiece becomes submerged. Octo is a little more sensitive.

Can a shop return regulators only used once in their pool? Or am I screwing the shop by doing that? I got a killer deal but I'm really starting to wish I had paid more at the other dive shop because I'm not sure how much confidence I have now.

 

[Macan]

1. Nope. Double nope. I couldn't get either my primary or octo to freeflow no matter what I did out of water. In fact, when I push the purge on the side instead of middle for the half purge, I get NO purge. No massive flow when holding the purge button either, fairly told.

@Scuba Doobie Do,

This means that your 2nd stage is “detuned” beyond it’s optimal setting. The fix can be simple to a bit more involved.

Simple fix: Go back to the shop and ask them to tune the 2nd stage per specs. This means that they have to use the Apeks Lever Height Setting tool and adjust the metal seat as needed. The tool has two sides. One side when inserted into the purge button should FLOW air. The other side when inserted should NOT FLOW air. It is likely that your reg is not flowing air at all irregardless of which side of the tool is inserted into the purge button. This can happen when the technician tries to manually adjust the lever height and (deliberately or unintentionally) detuned the reg a bit more than required vs. using the Lever height setting tool to set the cracking pressure.

Involved fix: When using the Lever Height setting tool to tune the reg, if the 2nd stage continues to flow air (ie leak) after the tool on FLOW side is removed and adjustments made , the 2nd stage has to be taken apart and reassembled. Most likely culprit is the Silicone Seat that has not taken a proper set. See my earlier message on this. They just need to replace the small Silicone Seat, reassemble and tune the reg per specs using the Lever Height Setting Tool. If that doesn’t work, then the next thing I would check carefully is the Spring Adjuster. This is the plastic piece that’s inside the Adjusting Screw (Inhalation knob). If set too deep, it will detune the reg beyond specs causing it not to freeflow.