help me make my xtx50 free flow

[Nick B]

I bought two XTX50s with some Tek3s on eBay. They're in pretty good condition. I've disassembled, cleaned and re-assembled the two second stages so far. I've used an Apeks service kit so its a new seat and o-rings in the regs.

For one of the two xtx50s I can't find a lever height setting that allows the reg to free flow when purging with the venturi and micro adjuster both at +max. I've taken the lever height to the point just before there is a small constant flow, so the reg is bordering on opening when the No GAS part of the face plate tool is used, and I have re-assembled the reg completely a couple of times now to check all the parts. I'm testing it using a DS4 I know is good.

Both regs breathe fine, had no obvious issues with parts when assembling, and the cracking pressure is set very similar to my other Apeks (stuck in some water they all start to crack just after the hose starts to get wet). But this one reg simply refuses to free flow.

So two questions:

1) I've never quite fully understood why it HAS to free flow - is it just as simple as thats how you know its going to give as much gas as possible when you absolutely need it?

2) Can anybody point me in the right direction for obvious culprits to check next if I really should ensure that it does free flow when purged.

 

[Sevenrider860]

The one thing I can think of is to double check to see that your spindle collar is installed correctly. The valve spindle hole needs to face the top of the case.

 

[Nick B]

The one thing I can think of is to double check to see that your spindle collar is installed correctly. The valve spindle hole needs to face the top of the case.

Yeah, definitely is. Checked that several times to make sure I was kidding myself.

 

[Sevenrider860]

Well that was the easy one... Another possibility is that the lever is bent or actually catching on the valve spindle some how. Hopefully some of the Apeks overhaul/repair experts (I am not one of them) will chime in with their thoughts.

 

[tbone1004]

aside from the manual actually stating it, you have to make sure the IP is high enough to actually induce a freeflow. If the IP isn't high enough, it won't go. The XTX's don't have a deep purge button and it not freeflowing from the purge isn't necessarily a bad thing. Make sure your IP is at 140-145, if it's any lower than that, it won't go.

 

[Nick B]

aside from the manual actually stating it, you have to make sure the IP is high enough to actually induce a freeflow. If the IP isn't high enough, it won't go. The XTX's don't have a deep purge button and it not freeflowing from the purge isn't necessarily a bad thing. Make sure your IP is at 140-145, if it's any lower than that, it won't go.

IP is 9.5 bar so in the right range. The other xtx50 and an atx40 happily free flow when I swap them in to confirm.

 

[tbone1004]

personally I wouldn't worry about it, but I'd make sure that the lever is freely moving as it could be catching on something. Sometimes they will get ever so slightly off center which will cause them to catch on the barrel.

 

[Nick B]

personally I wouldn't worry about it, but I'd make sure that the lever is freely moving as it could be catching on something. Sometimes they will get ever so slightly off center which will cause them to catch on the barrel.

I'll be checking it all again before testing it in the pool. The lever seems to be moving freely enough.

 

[Sevenrider860]

I have two XTX50 second stages on my work bench, so I just checked. IP was 135 and both will free flow with a quick tap to the purge button. I even adjusted the IP to 125 (below specifications) and the regulators will still free flow with a tap to the purge button. 130 to 145 is considered an acceptable IP for the TEK3 and the second stage should free flow within that range with a tap of the purge button when the adjusting screw is loosened and the venturi lever is set to "+".

Another thing you may want to try is to swap major components. If you switch the valve spindle/lever assembly between the two cases, does the problem travel with the valve spindle/lever or stay with the case? If you turn the venturi switch to "-" the regulator will not free flow. So this step is also a verification of case geometry and venturi function and switching the case could identify that. Also, while unlikely, one of the checks is to swap the LP hose as it could be clogged or obstructed and restricting flow.

 

[Nick B]

Another thing you may want to try is to swap major components. If you switch the valve spindle/lever assembly between the two cases, does the problem travel with the valve spindle/lever or stay with the case? If you turn the venturi switch to "-" the regulator will not free flow. So this step is also a verification of case geometry and venturi function and switching the case could identify that. Also, while unlikely, one of the checks is to swap the LP hose as it could be clogged or obstructed and restricting flow.

Wife and kids are out tonight so I might just spend some more time on it.

It's not the LP hose as I used the same one for all the regs.

I didn't really consider that the case could impact it as all the mechanical parts slot in where they're supposed to without issue. I did notice the faceplate was very stiff to get off and difficult to bed back the last quarter turn but I can't see that making any difference to the free flow...yet

---------- Post added September 13th, 2015 at 10:27 AM ----------

The one thing I can think of is to double check to see that your spindle collar is installed correctly. The valve spindle hole needs to face the top of the case.

OK, I'm going to 'fess up.When I started stripping the regs down side by side I noticed that though the spindle hole was pointing up, it was actually pointing very slightly forward of directly up compared to the correctly assembled reg and so causing a venturi effect that would prevent the free flow. This was because...The collar was not installed properly. I hadn't removed it or the lever when disassembling and dumbly assumed it was correctly installed because the spindle hole pointed (generally) upwards and I also assumed that it couldn't be incorrectly installed and assembled. But it wasn't correctly installed and you can still put everything together that way round and it will work despite the holes for the lever feet being slightly off-centre.Assumptions, assumptions.