Mares Mr22 hard breathing and squealing at depth

[Adr1an]

Hello everyone,
I need a quick advice from those familiar with this regulator. I'm in Sharm (Red Sea) right now and my Mares setup (MR22 1st with Abyss 2nd) is noticeably harder to breathe from once I get deeper then 10m (33ft or so) and also starts squealing noticeably. Played a bit with the 2nd stage adjustment at the dive center (they had the 5.5mm tubular key and so on) but it looks like the problem comes from the 1st stage. On land IP is stable no matter how many times I cycle the regulator.
When I dive the breathing is increasingly hard with depth, not to the point where I would choke or something but still very noticeable and also accompanied with this noise.
I'm not sure whether this could happen due to a poorly lubed o-ring in the 1st stage. Is there something easily accessible that I could lube in the Mr22? I'm quite familiar with the 2nd stage but the 1st was so far serviced by trained technicians. Don't have time to get it serviced here so if someone is very familiar with this reg I would appreciate A LOT the advice

 

[JackD342]

I can't picture what is happening in the 1st stage, but there is nothing "easily accessible" to lubricate.
Symptoms aside, my first check point is to see if a new poppet was installed on an old removable seat. Original seats should be upgraded to new versions, as old poppets are out of production. I am not sure what symptoms a mismatch would manifest though. Maybe the spring is over tightened to make up for the poor seal with the mismatch?
Also, the 2nd stage adjustment requires BOTH correct lever height AND orifice adjustment, not just one adjustment setting.

 

[Adr1an]

Thanks Jack, yes I know about both adjustment points on the 2nd, mentioned just the 5.5mm tubular key as that one is harder to find.
About the 1st stage, is there anything I can do short of a complete overhaul? The regulator breathes VERY well at surface and down trough the first 9m or so.
What I fear is that the o-ring on 1st stage poppet could be poorly lubricated. But thin it should make noises at surface as well, right?

 

[JackD342]

Non obvious possibilities are a partial blockage with debris somewhere in the airflow. Experienced on more than one cylinder so far?
If an oring issue between poppet and HP balance chamber, I would expect a leak and higher pressure, not reduced flow.
Worn out springs? How close is the main spring adjuster to the edge of the body? If it is several threads different in either direction, that is an indication something inside is not right. IP should be 145 psi +/- 3psi.

 

[Bob DBF]

Check the filter at the input to the first stage. If the filter is clogged it will decrease airflow at depth and the disruption of the airflow could cause noise.


Good luck

Bob

 

[Adr1an]

Thank you guys, IP is being shown at 140 but the gauge may be a bit off. The filter doesn't look clogged but I have a spare with me so I will replace it and come back with the result.

P.S. Main spring adjustment nut is 2-3mm over the threaded cap (in height).

 

[Zef]

I Played a bit with the 2nd stage adjustment at the dive center (they had the 5.5mm tubular key and so on)....

I was under the impression the Abyss 2nd stage has a 5mm fitting for the adjustment on the side where the hose connects. Was there a change on newer editions? Or is 5.5mm the size of the lock nut on the demand lever?

-Z

 

[Adr1an]

The size of the lock nut on the demand lever. That's relatively hard to find in the field (so to speak). On the other hand, the Allen wrench set is available on pretty much any boat and dive center, that's why I didn't mentioned it earlier.

 

[USdiver1]

Non obvious possibilities are a partial blockage with debris somewhere in the airflow.

Is your 2nd stage hose of the MiFlex variety? They can deteriorate over time and create a partial blockage.

 

[Adr1an]

I sorted it out, the cause had nothing to do with the 1st stage. The 2nd stage poppet seat was the culprit. Will post in detail when I get home.
Thanks again to everyone who offered advice.