Question First stage environment seal pressed in on one side?

[Vipr]

Hi I have purchased an apeks XL4 ocea recently.

Before taking delivery of the product I had requested them to adjust the regulator for first dive free flow and perform a bench test.

They have done so and shipped my product to me.

Upon receiving it I noticed that the rubber environment seal on the first stage appears pressed inside on one side of it.

Upon enquiring about it the service technician has replied stating the following: "I am the Apeks/Aqualung/Tecline Regulator Technician Trainer here, when the regulator is serviced correctly we press down the environmental seal as per Apeks servicing standards, if the seal is popping up then it indicates that there may be a leak in your 1st stage o-rings".

I am a bit concerned diving with this regulator unless I have some proper clarity about this as everywhere online it says that this is not right.

Can someone take a look at the following image and let me know about this ?

 

[gratefulmjc]

Hi @Vipr. If you had a leak, the environmental seal would likely be uniformly flat...not drawn in on one side as shown in the pic you posted. It being partially drawn in indicates that the environmental chamber contains, as intended, a slight vacuum (but perhaps not as much as intended).

Try this:
1. Put your reg on a tank and open the tank valve to pressurize the reg...the environmental seal should relax outward and be basically flat...not bulging outward.
2. Close the tank valve then purge a second stage to depressurize the reg...the environmental seal should return to being drawn inward as seen in the pic you posted.

If after Step 2, the environmental seal does not get drawn inward as in your pic (or is actually bulging outward), you have a leak. I believe the leak would be at the diaphragm end of the environmental chamber vice the environmental seal end of the chamber (if the leak was at the environmental seal end of the environmental chamber, I believe the environmental seal would relax to a flat shape without having to pressurize/depressurize the reg).

Cheers, mjc.

PS. When the end cap is installed to hold the environmental seal in place on the diaphragm clamp, the service manual says the reg should be on a tank and pressurized. A pressurized reg causes the diaphragm to be bowed outward toward the environmental seal while it and the end cap are installed. Then, when the tank valve is shut off and the reg depressurized, a spring pushes the diaphragm away from the environmental seal causing the slight vacuum mentioned above which draws the environmental seal inward as shown in the pic you posted. It is not sufficient to just press the environmental seal down in order to obtain the slight vacuum mentioned above.

 

[Vipr]

Than

Hi @Vipr. If you had a leak, the environmental seal would likely be uniformly flat...not drawn in on one side as shown in the pic you posted. It being partially drawn in indicates that the environmental chamber contains, as intended, a slight vacuum (but perhaps not as much as intended).

Try this:
1. Put your reg on a tank and open the tank valve to pressurize the reg...the environmental seal should relax outward and be basically flat...not bulging outward.
2. Close the tank valve then purge a second stage to depressurize the reg...the environmental seal should return to being drawn inward as seen in the pic you posted.

If after Step 2, the environmental seal does not get drawn inward as in your pic (or is actually bulging outward), you have a leak. I believe the leak would be at the diaphragm end of the environmental chamber vice the environmental seal end of the chamber (if the leak was at the environmental seal end of the environmental chamber, I believe the environmental seal would relax to a flat shape without having to pressurize/depressurize the reg).

Cheers, mjc.

PS. When the end cap is installed to hold the environmental seal in place on the diaphragm clamp, the service manual says the reg should be on a tank and pressurized. A pressurized reg causes the diaphragm to be bowed outward toward the environmental seal while it and the end cap are installed. Then, when the tank valve is shut off and the reg depressurized, a spring pushes the diaphragm away from the environmental seal causing the slight vacuum mentioned above which draws the environmental seal inward as shown in the pic you posted. It is not sufficient to just press the environmental seal down in order to obtain the slight vacuum mentioned above.

Thank you for the detailed explanation. I will get the regulator checked again with another dive shop just in case.

I used the reg today for 4 dives and it performed excellently. No issues whatsoever. I will check about the seal getting pressurised and going flat once pressurised tomorrow during my dives again.

 

[gratefulmjc]

No prob...happy to share my 2 cents as others have done here on SB to answer my posts.

Glad the reg worked well.

Having a touch more air in environmental chamber than intended should not be an issue. The intent of getting as much air out as possible is so that the environmental seal rests directly on top of the hydrostatic transmitter, the opposite end of which rests on the diaphragm. The diaphragm, in turn, controls the valve that controls the flow of gas from your tank through your first stage and into your second stages.

When you descend (or ascend), the water pressure increases (or decreases) causing the environmental seal to push against (or pull away from) the hydrostatic transmitter which in turn pushes against (or pulls away from) the diaphragm. This enables the first stage to increase (or decrease) the pressure supplied to your second stages to compensate for the water pressure you encounter at a given depth.

If the air is not sufficiently removed from the environmental chamber, the environmental seal won't rest directly against the hydrostatic transmitter. As you descend, the environmental seal first has to compress a little air before it rests directly on the hydrostatic transmitter and then operate as mentioned above.

However, though I haven't done the math, I can't imagine that the additional pressure from the water needed to compress that small amount of excess air in the environmental chamber to the point that the environmental seal contacts the hydrostatic transmitter will be noticeable. Take a look at other divers' diaphragm regs (unpressurized); you probably will see environmental seals that are not pushed inward...yet no one is complaining about poorly performing regs.

 

[Centrals]

An inexpensive Intermediate Pressure Gauge is very useful to monitor the stage of the HP seat.

 

[runsongas]

the environmental seal is supposed to be sucked in a bit when the reg is not pressurized, it will be flat when you hook it up to a tank and turn it on.