BOV Free Flow / Gas Leak

[piranhaman00]

Hello,

I have a question regarding BOVs in general but in my case specifically the Divesoft BOV. I am new to CCR and opted for BOV which was in contrast to what people around me dive which is only DSV. I was told that BOVs are all 'cheap second stages' that will free flow in the colder water temps I dive, 38-60F. I did some research and landed on the Divesoft as the Apeks second stage is said to have good cold resistance.

Well, after 20 or so hours, I am finding I do get 'free flows' from the BOV. They only occur when I use the BOV and then switch back to CC, the BOV will leak gas, evident from bubbles escaping around the purge button. If I dont use the BOV at all during the dive, it does not free flow. At first the free flows were significant but I have adjusted the intermediate pressure of the BOV to a point where its difficult to pull gas from but still breathable. At this pressure, the gas leaks are small but present. It does appear to be temperature dependent, colder being easier to flow.

Divesoft recommended matching the IP of the 1st stage and BOV but imo that would only make the problem worse as that would allow more gas to free flow.

Anyone use BOVs in cold water successfully? Any tips or ideas on this issue? I could still keep tuning down but soon I will not get any gas from BOV which is counter productive

Thanks!

 

[Jhgt2d]

@Tracy may have some suggestions.

I also have a divesoft BOV and dive 40ish F water all summer out on the lakes. No leaks or free flows even when practicing bailout ascents or sanity breaths during the dive.

The honk is annoying, but so far I have enjoyed having my BOV. No regrets so far.

 

[tbone1004]

Hello,

I have a question regarding BOVs in general but in my case specifically the Divesoft BOV. I am new to CCR and opted for BOV which was in contrast to what people around me dive which is only DSV. I was told that BOVs are all 'cheap second stages' that will free flow in the colder water temps I dive, 38-60F. I did some research and landed on the Divesoft as the Apeks second stage is said to have good cold resistance.

Well, after 20 or so hours, I am finding I do get 'free flows' from the BOV. They only occur when I use the BOV and then switch back to CC, the BOV will leak gas, evident from bubbles escaping around the purge button. If I dont use the BOV at all during the dive, it does not free flow. At first the free flows were significant but I have adjusted the intermediate pressure of the BOV to a point where its difficult to pull gas from but still breathable. At this pressure, the gas leaks are small but present. It does appear to be temperature dependent, colder being easier to flow.

Divesoft recommended matching the IP of the 1st stage and BOV but imo that would only make the problem worse as that would allow more gas to free flow.

Anyone use BOVs in cold water successfully? Any tips or ideas on this issue? I could still keep tuning down but soon I will not get any gas from BOV which is counter productive

Thanks!

the second stage is balanced so you should absolutely not be messing with the IP to try to deal with freeflow issues, if you lower the IP too much you're at serious risk of not providing enough gas which is deadly in a hypercapnia incident.

If it's freeflowing you have to figure out why, and that's usually going to be the adjustment of the cracking effort of the BOV itself, same as you would any other second stage that is exhibiting similar issues. That is never done by adjusting the IP out of factory spec. Second stages that are tuned light are prone to freeflowing after a few hours of use, completely normal behavior and the remedy is properly adjust the cracking effort of the second stage.

 

[piranhaman00]

the second stage is balanced so you should absolutely not be messing with the IP to try to deal with freeflow issues, if you lower the IP too much you're at serious risk of not providing enough gas which is deadly in a hypercapnia incident.

If it's freeflowing you have to figure out why, and that's usually going to be the adjustment of the cracking effort of the BOV itself, same as you would any other second stage that is exhibiting similar issues. That is never done by adjusting the IP out of factory spec. Second stages that are tuned light are prone to freeflowing after a few hours of use, completely normal behavior and the remedy is properly adjust the cracking effort of the second stage.

Sorry, I meant cracking effort. No adjustments made to the first stage IP. I am making adjustments to the cracking pressure on the second stage using the coarse adjustment screw where the LP hose screws onto the second stage.

 

[Fat old english bloke]

Not answering your question as such, but I’m a fairly new BOV user (standard equipment on my little unit) and have experienced a couple of minor freeflows, all fixed underwater without really effecting the dive.

I was a little concerned that a freeflow I cannot stop could make the dive very uncomfortable, so added a flow-stop/shut-off. I also always dive with a necklaced back-up coming from my non-dilout bottle.

My other CCR has a nice and comfortable DSV, which I might yet swap for a BOV, or vice versa on the little unit. I think I’d like about 100-150hrs on the BOV before I make a decision.

 

[Etmar]

I have rEvo BOV (Mares) connected to bailout cylinder. In winter I regularly dive in cold waters 1-3 degrees Celsius.
BOV has twice in three years leaked small bubbles and adjusted in service. No problems after that.
Anyway, I have a DSV-loop as a spare part with me just in case when driving to distant divesites in winter.

 

[piranhaman00]

Issue resolved with further adjusting of cracking pressure. Thanks.

 

[justinthedeeps]

The water temp hasn't been any issue. 100+ hrs on the Divesoft BOV, min temp ~6°C, max depth 110 metres, very satisfied overall apart from a few particulars below

Does your BOV have the external spring tension adjustment knob, but this is insufficient to stop the free flow?

Probably a routine second stage crack adjustment as long as your IP is within spec? I would guess Divesoft suggests sending it in for readjustment and servicing.

Separate issue from the OC stage, but also be aware the the Divesoft BOV has some rather thin and fragile silicone o-rings in it--or at least mine does--which can get chopped if they swell and/or get caught up on sharp internal edges. My only BOV leak so far was due to this. It is probably an additional reason why they warn against using silicone lubricants. I was at one point able to buy spares on the e-shop for relatively simple field maintenance and repairs, but this was discontinued and I was told it had been made into an exclusively a send-in servicing matter...

It would be much nicer to have the spares on hand and be able to perform re-lubrication more regularly in ~30 minutes, anywhere in the world.

Another thing that can happen with these is that if you ever descend on the BOV with no IP supplied, such as a closed cylinder or inline shutoff, the second stage diaphragm can get sucked into the reg causing separation of a silicone ring from a plastic insert (it is not a full-radius solid diaphragm, as in some other second stages). This too can result in leaks and wet breathe. In my case it was not actually damaged in the process and could be re-seated. A spare for this was also not available for purchase