Troubleshooting Flathead VI 1st stage high IP

[ElGaucho]

I started to rebuild my Zeagle Flathead VI. I disassembled it, cleaned all the parts, and now when attempting to get it back in it´s original shape I hit a brick wall every time I test it. It goes all the way to 250 psi IP and then I basically close off the valve (I have an OPV on my IP gauge that opens at 250).

I have tried at least 5 times to redo the whole process trying to find where I have done wrong. Honestly I can´t. Everything is by the book (service manual), nothing seems off or damaged in any particular way. I have made sure I have followed the instructions to the letter. I always get this high IP (keeps climbing).

Anyone want to take a wild guess? Or maybe from experience can give me a pointer of what might be wrong?

Thanks in advance.

 

[herman]

Have you replaced the balance chamber Oring (again)? Are you sure you did not scratch the inner wall of the balance chamber? Either one will cause bad IP creep.

 

[ElGaucho]

I guess the balance chamber o-ring is number 33 on the Flathead exploded view? I actually replaced that one twice, thinking I might have overstretched it when installing it after lube. The scratching, I don´t thik so. Now this is no "creep". This is not even a violent creep. If you slowly turn the valve, it will go straight to 250 (where my opv blows). Thanks for the input.

 

[herman]

If that's the case, then you have a major flaw somewere. To get that much air that fast, you are either missing an oring or something is holding the HP seat open. Start by removing everything from parts 1-10 (assuming you are looking at the same manual I am). Basically everything from the lifter out. Next carefully pressurize the reg. If you don't have any leaks at this point, you either had something in the wrong place or badly misadjusted (the spring adjuster is adjusted full out??) You can depressurize the reg by putting the lifter back in and pressing it with your finger. Next install parts 5-10 but just barely install the adjuster, just enough to barely touch the spring. Repressurize, your IP should be way low if any at all. Now increase the IP with the adjuster.

If you do have a leak, it either has to be coming from the balance chamber, the HP seat or one of the seals in between. Difficult to tell you which from here.

The balance chamber oring is 32, the tiny one that goes in 35.

 

[ElGaucho]

Herman:

Thank you so much for your help. Actually I figured out the problem, and it was a rookie simple mistake. But the troubleshooting idea you gave me of removing 1-10 and focusing the problem solving on half of the equation proved the correct way of finding my mistake. Even with 1-10 removed I would still get a complete free flow. So what was wrong was evidently what was sealing between the HP chamber and the LP chamber. Well, the guy that makes that seal is o-ring No 33.

I removed it, checked it, and had the brilliant idea of rechecking it against the o-ring table in the manual. I was using o-ring 18 size instead of o-ring 33 size in that location. It was just a tad smaller than it should, thus it was not sealing, thus the constant free flow and the very high IP. Once I exchanged it with the correct size, everything started working just fine.

Thanks a lot again, no matter how many books and articles you read, it's not until someone gets you to think over the mechanics and the physics (and troubleshoot through that) that you begin to actually learn.

 

[herman]

Happy to help. That is the standard trick I use on any diaphgram first stage that has problems.