Atomic Regulator hissing. Is this normal?

[Sonic04GT]

Just got my B2 back from overhaul. With the adjustment knob turned all the way out (lightest breathing), if I purge the regulator, it lightly hisses for another 10 seconds or so once released. If I put the adjustment screw in a couple of turns, it stops as soon as I release the purge.

Is this normal, or should I take it back to the shop?

Just got my Z2 octo today and with the screw turned all the way out, it doesn't do that.

Intermediate pressure is about 130-135. Once I pressurize the rig, it doesn't begin to freeflow until I breathe off of it or press the purge.

Edit: Playing with it again, it seems worse. The hissing doesn't seem to stop. If I exert pressure on the knob, it also stops the hissing until I take my finger back off. See video. Notice when I turned the knob the airflow stopped, but began again once I purged.

I haven't been diving in quite a while, but I've had this regulator for 9 years and I don't recall it doing that. Not sure.

Is it a simple adjustment of cracking pressure? I say simple, but I've never messed with it.

 

[fmerkel]

Sounds like they slightly over tuned it. If the IP is stable, and you can stop the flow with the adjustment knob, then you can either:
1. Live with it. Personally I will sometimes tune my regs like this.
2. Take it in and have them re-tune it. If you give them a warning they may be able to do it on the spot in just a few minutes. Easy procedure.

The seat will sometimes take a set (dent/groove) after the overhaul and that little bit of extra room now allows air to seep past. By adjusting the knob, or pushing on it, you move the seat into the poppet and stop the flow.

The octo is likely tuned to crack harder, also a normal tuning process. You don't want it to free flow as easily since it's just hanging out there in space.

 

[snowdog61]

your cracking pressure has been adjusted to the bleeding edge - easiest breathing. You can adjust it yourself or take it back to the shop and they can do it for you or you can simply dial it in and not worry about it. It really shouldn't be adjusted that loose but you do know you are at the lowest cracking pressure possible on that reg. With a fresh rebuild, there is usually a set that the orifice will take and with enough cycles, it may actually get a bit worse. If you have a hex key set, adjust it yourself so it just stops with the knob all the way out.

 

[snowdog61]

heh - yeah, what fmerkel said

 

[Sonic04GT]

Thanks for the quick replies. Good to know it's not anything to really be concerned about. Where do I adjust it?

I'd like to take a look myself, but if there's any concern, I'm just going to take it back to the shop.

 

[snowdog61]

remove the 2nd from the LP hose. Inside there will be an adjustable orifice that has a hex adjustment. A very slight clockwise turn (1/16 - 1/8th) should get you there - hold the purge button in while doing this to take pressure off the seat (not sure if that model has the seat saver feature but won't hurt otherwise and is just a good practice). re-assemble and put it back on the tank with the cracking pressure adjuster all the way out and check for leakage, cycle the purge a few times.

 

[Sonic04GT]

Is it this flat head adjustment?

 

[snowdog61]

ok same thing but obviously with a flathead I tune mine so it just barely stops and usually am dialing the cracking pressure knob in on the way down to the bottom once diving. This insures you are at the lowest cracking pressure possible. As long as your IP is steady, there shouldn't be issues with your 2nds until the seat get so bad (grooved) that you need excessive pressure to keep it from dribbling past - it'll be much harder to pull on (breathe) to get the cracking pressure to where it'll start to flow past the seat. invest in an IP gage if you haven't - relatively cheap and plug directly into the LP inflator hose. You'll know whether you need to service or adjust. You've got the adjust part covered it seems.

 

[Sonic04GT]

Got it. Thank you gents. Learned something new today

Took a few trial/error attempts, maybe 1/4 turn in total, but it seems good now. I set it to where I just ever so slightly have to turn the adjustment knob to stop the freeflow. Now that I know how it works, I'm just going to dive it for lightest breathing, and adjust in the future if necessary.

 

[snowdog61]

So since you seem interested, you can check cracking pressure by slowly submerging it in the sink with the mouthpiece up - on tank pressure of course. You should start to get flow before it goes under. Easiest is to just breathe off it - should be like you remember it