Freeflow?

[WeldonDowd]

I bought a used MK16/S550. When I take it out of my mouth at depth it freeflows. I have only rented regs before so didn't know if this was normal and they set the rentals to breath different. It breaths fine, just flows air when I take it out of my mouth. I put an octo on it myself and the octo doesn't freeflow (just a little more info for you, if it helps).

 

[parzdiver]

While I am not a service technician, I have been spending time with one in the shop. This should be a simple adjustment on the second stage which any service technician can do.

Since your octo isn't doing the free flow, I assume your intermediate pressure is okay.

 

[WeldonDowd]

"Since your octo isn't doing the free flow, I assume your intermediate pressure is okay."

As new to diving as I am, I thought the same thing. When I called a dive shop near me, he said it was the Intermediate on my first stage, I told him the octo didn't freeflow and he said to bring it in. Not sure I want to bring it to him.

 

[parzdiver]

"Since your octo isn't doing the free flow, I assume your intermediate pressure is okay."

As new to diving as I am, I thought the same thing. When I called a dive shop near me, he said it was the Intermediate on my first stage, I told him the octo didn't freeflow and he said to bring it in. Not sure I want to bring it to him.

In thinking about it a little more, I assumed the IP is okay, but the octo might be de-tuned enough that a high IP would cause it to free flow like your primary. Any service on the reg should check the IP anyway to verify it is okay, followed by the cracking pressure on the second stage.

As I said, I'm not a technician, I just spend way too much time talking to them. As long as the service charge is reasonable, I would take it in. When was the last time the regulator was serviced?

 

[captndale]

You say that the regulator freeflows when you remove it from your mouth. Are you holding it with the mouthpiece down, horizontally or up? If you are not turning the mouthpiece down as you remove it from your mouth, you might expect a precisely tuned regulator to free flow. If, however, you are turning the mouthpiece down and it still freeflows, you should check to see if it is free flowing while it is in your mouth. Many divers do not notice when their regulators continue to flow a small amount of air during the exhalation phase of their breathing cycle. It is important to remain aware of the performance of one's regulator during the exhalation phase as well as the inhalation phase. In cold water this will often be a precurser to a regulator freeze-up. If there is a small leak while you are not breathing in, either under water or on the surface, your second stage needs a small adjustment. Turning the orifice seat in about 1/4 should take care of it.

 

[halocline]

I bought a used MK16/S550. When I take it out of my mouth at depth it freeflows.

That's normal, especially if you inhale then immediately take it out. Try turning it mouthpiece down, see if that stops it. Also, there's a venturi assist knob (it'll say min/max) on the reg, turn it to min. That should help.

 

[parzdiver]

I bought a used MK16/S550. .

I missed this part. If you haven't gotten it serviced, I would recommend a service overhaul. This will replace any "consumable" parts like o-rings and check all the pressures for proper operation. If you are still having problems after the service, the shop that did the service should stand behind the service and work with you until the problems are resolved.

 

[WeldonDowd]

I was gonna wait to get it serviced when it gets cold, but maybe I'll go ahead. Capt Dale, I'm almost positive it wasn't freeflowing in my mouth; I was really paying attention to it during the three dives I did with it. It was very easy breathing but didn't fill my mouth with air unless I inhaled. I did however hold it with the mouthpiece down while out of my mouth and it still flowed air. The only reason I took it out of my mouth was to breath from my octo to see how it was. I did three dives with this regulator at about 25 feet. Dive 1: 1 hour 30 minutes, Dive 2: 1 hour 45 minutes, Dive 3: right over 2 hours. My brother was my buddy and our air consumption was identical so I don't think the reg was waisting air by freeflowing in my mouth. Is turning that orifice seat in a little something I can do with tools at my disposal? I do have the service manual but haven't studied it hard yet.

thanks for the info everyone

 

[halocline]

You might be able to adjust the orifice but it's not necessary. As long as it doesn't flow in your mouth don't worry about it. If it's out and flowing, put your thumb over the mouthpiece, it will stop, and let it fill with water, then it won't flow. Or, if it does, then just get it serviced.

This reg has a very strong venturi assist that will really aggravate free flows. Diving with the VIVA knob in the minimum setting should help quite a bit.

I think this reg has a seat saver like the S600, if so, it might not be as simple as just tightening the orifice, but if you want to try, disconnect the hose from the 2nd stage, you'll either need the SP special wrench or some carefully padded pliers, then look inside and you'll see a white plastic part with a slot in it. Depress the purge, and turn the slot about 1/10 of a turn clockwise with a screwdriver, then put everything back together and try diving again.

If you have a tank, you can check it out before doing anything else. Fill up the tub, sink the pressurized reg, let it fill with water, and see if any bubbles escape. Remember the venturi knob, and I bet anything you have no leak.

 

[WeldonDowd]

Muchos Gracias mattboy, I'm gonna keep diving with it then and get it serviced when the water gets to cold for me.