G250? Worth servicing?

[buddhasummer]

When tunning a G250 should the Venturi be on min or max? I thought max but VH book says min. I'm having some difficulty tuning them they either leak or are hard to breath. Cheers.

 

[rhwestfall]

nothing to do with the venturi....

that is orifice/lever height... I'd check that you have the poppet in correctly and the feet of the lever engaged correctly on the poppet "ledges". You might have the poppet in upside-down or not all the way seated (been there, done that)

go to the VDH site and look in the catalogs for the poppet changes document. Study the cut-away picture as to how it all goes together..

 

[buddhasummer]

Thank you Bob. They are "now" correctly assembled, although the first time I'd fitted the poppet the sting way around in error and only found out by chance after tuning and term screwing adjustment know all the way in at which time air flow completely and instantly stopped and the lever became stuck closed/ poppet jammed against the oriice. Glad I found that out before I was actually diving them, that would have increased my heart rate somewhat. I'll take a look at the seat as it's possible I damaged it during assembly. I'll disassemble them and start over, I do have a spare seat. cheers.

 

[Zung]

I always leave the venturi midway and never touch it; like Bob said, it has nothing to do with tuning.
Starting over is a good idea, take you time and go step by step. Pete Wolfinger, of Regulator Savvy fame, has published a repair guide for the G250; refer to it in case of doubts.
The seat may still work, it's not easy to get, so it's worth saving.

 

[buddhasummer]

Thank you the advice. I disassembled and re assembled today, what a nightmare I could not get the poppet to click past the lever, I tried for over an hour. I attempted to fit into a spare air barrel that I had lying around and without office it clicked past no problem at all. I removed oriface from my G250 and sure enough it clicked in no problem. But as soon as the orifice was installed, no go. I backed the orifice out as per instructions 1.5-1.75 turns but still no go, backed off 2 turns as a previous post by Zung, still no go.

Backing it off 2.5 turns the poppet finally clicked into place. The Oricice I have is a new orifice as used in the G250V. It is a little taller by side but the thread length looks the same so I'll assume it still bottoms out at the same depth.

I compared the new seawing style poppet with the original and the "legs" one the newer style seem to sit about 2mm higher in relation to the original. I'm wondering if this is what was causing the issue? I disassembled and reassembled many times to ensure the same out come and it was 100% consistent. The poppet would not click in place unless the orifice was backed out at least 2.5 turns. The lever does not look to be bent.

Tuned as per Peters instructions, same as VH book also.

Initially was cracking at about .6-.7, played with dropping the lever height in an attempt to get a reading of the prescribed 1.4-1.6 range, if I got that range the lever was then so low the purge ceased to function.

The "best" balance to could get was about .9-1.1".

I have no idea how it's going to work out. I'll dive them again this week assuming to predicted typhoon doesn't actually happen and post back.

If anyone can see something obvious I'm doing wrong and knows if my suspicions re the poppet not clicking unless orifiac is way out is a correct suspicion and or has encountered similar issues I'd love to hear.

Cheers.

 

[buddhasummer]

PS for comparison, I installed the original shorter orifice but the poppet would still not click past the lever. So by process of elimination it "must" be the newer seawing poppet causing the problem.

Could the lever be bent and it not be visually noticeable? Looking down the barrel with a torch it looked to be ok, and the upper outside part didn't look to be bent in anyway.

 

[buddhasummer]

Something I've never seen before also, if one second stage free flowed after purge was fully depressed with Venturi on max the other second stage would also start violently free flowing even though I had not touched it.

 

[buddhasummer]

FWIW I've been servicing Apeks regs for some years and have never encountered an issue. I must be doing something wrong here.

 

[NotSure]

Backing it off 2.5 turns the poppet finally clicked into place. The Oricice I have is a new orifice as used in the G250V. It is a little taller by side but the thread length looks the same so I'll assume it still bottoms out at the same depth.

I think your assumption that the G250V orifice is bottoming out at the same depth may be your problem. All of the issues you are having could be explained by the orifice bottoming out deeper. If they are bottoming out the same I believe the difference in the length of the orifice should be the same as the difference in the depth them bottomed out. If you have a set of digital calipers available it might ease your mind to do the measurements.

 

[buddhasummer]

Thanks for your reply. I had the same issue when I swapped out with original orifice, so looks like that is not the issue. But when I swapped back to original poppet regardless of which orifice I used the poppet would click into place. I'm leaning toward the poppet causing the issue.