How does immersion test affect reg. after service?

[nohappy]

I've done some services on my own reg. At the end of each service I put the reg (attached with tank) into a sink full of water to detect bubble. Sometimes, I found that after I was sure there is no bubble underwater after few minutes and pull it out, second stage somehow start to leak (or small amount freeflow). The leak won't stop even if I put fingers on the mouthpiece.
The breathing test and the IP/cracking effort is in the correct range and there is no leak at all before the immersion test.
Does anyone has similar experience? How does immersion test affect reg? I'm glad I did that test otherwise it seems normal (no freeflow at all before the test).

 

[JackD342]

I think it is just coincidence that you notice it after an immersion test. It probably would have happened anyway after you operated the 2nd stage a few times, in different orientations.

First impression is the seat is not sealing well or consistently, which can be any number of causes.

You give no details on what brand/model you have, so don’t expect anything specifically helpful to be forthcoming.

 

[nohappy]

Thank you @JackD342. One reg. is AquaLung Legend 1sts stage (but I forgot if it's Legned second stage or Calypso oct that leaks).
Another case is a second stage which comes from a local brand in my country you probably never heard of, but it attached to Apeks xtx50 first stage.

I asked this question because I want to know
1. If the immersion test actually distribute some factors that affect reg and make it start to leak or it is just coincidence like you said.
2. If it's just coincidence, I want to know if there are some more extra tests I should add so that I can notice the problem before immersion test. Because I tried purge few times or breath few cycles before the immersion test and found nothing.

 

[runsongas]

if the IP is correct and locking up without creep, then check the second stage. lp seat, purge lever, orifice etc.

 

[nohappy]

I understood that.

I asked this question because I want to know
1. If the immersion test actually distribute some factors that affect reg and make it start to leak or it is just coincidence.
2. If it's just coincidence, I want to know if there are some more extra tests I should add so that I can notice the problem before immersion test. Because I tried purge few times or breath few cycles before the immersion test and found nothing.

 

[GJC]

How long, after service, are you doing the immersion? The seat may be settling in and creating a gap. This happens fairly frequently to newly serviced regs on their first dive and is caued by time, not immersion. Some service techs cycle the reg 100 times and wait a day or 2 before final adjustment and placing in service.

How old is the diaphragm? Pressing the purge puts direct pressure on the lever. Taking a breath or water immersion puts pressure on the soft parts of the diaphragm. If it's old, damaged or deformed your immersion test may be doing something to the diaphragm that won't happen during purge. This is probably unlikely to be the cause of what is happening to your reg, but may be it if you are sure it's not the seat settling in.

Another thing that may be happening is first stage IP creeping up with time. This is time related, not immersion. If the first stage is not sealing well, the pressure creeps up slowly over time until the second srage starts to leak. If you are doing your purge tests quickly after pressurizing your reg, there may have not been enough time to get to the higher IP to start leaking. And the reg may have been pressurized long enough to cause the leak during the immersion test.

Sorry if I'm giving you some info that you already know.

 

[JackD342]

Also, do you have the actual service guide to follow step by step, in order? Might be missing an adjustment, such as not setting lever height correctly for the Aqualung items.

 

[JackD342]

Just had a thought, since you are servicing on your own: You are replacing the seat and not reusing it, right?