Recommendations: Cylinder pressure gauge (surface, not submersible)

[Wibs]

Tired of inaccurate surface pressure gauges. Would like to buy a new gauge which is within spitting distance of the pressure. Wouldn't object to buying a digital one either as it'll be better for blending. A larger 3"/75mm would be nice. I have the DIN connector and pressure relief valve from an old gauge that consistently reads 10% low.

I realise that yer gets what yer pays for.

So, to start off, are there any "quality" brands which are generally good?

Digital gauges. These vary a lot in price. Would buying the eBay advertised "Digital DIN cylinder contents pressure check gauge 0 - 400 Bar 0.5% Accuracy" be a waste of the ~£120? Or going for the Narked one for a lot more?

Any other recommendations?


TIA

[notdeadyet]

Try SMP in Preston.

[colinicky]

I seem to remember way back when having a conversation with John @ narked & at that time being told that analogue gauge was more accurate than digital, be interested to know if that is still the case

[MikeF]

Undersea 100mm gauge. 275 bar 1%fsd should be good enough.

Doesn’t matter if it’s digital or analogue just so long as it’s (relatively) accurate. My digital transducer is 0.7% fsd but the more truly accurate you get the more you spend. Though the most accurate gauges also come with a calibration cert so you can compensate for the inaccuracy of the accurate gauge.

[Wibs]

Undersea 100mm gauge. 275 bar 1%fsd should be good enough.

That seems like the one. Good enough and not stupidly expensive.

I'm not after amazing absolute accuracy, but would like to know within a few percent, especially for bailouts.

For mixing, would use the whip gauge. This is the one I'm thinking of getting a digital gauge as whilst it might not be accurate to absolute pressure, it should be accurate to changing pressure, e.g. adding in 20 bar of O2 on top of, say, 150bar of absolute pressure. (Digital isn't more accurate, it's just easier to read a specific figure than an analogue gauge with or without a mirror)


Minor thread question: do 'standard' SPGs use 1/4BSP? What's the thicker thread size which both of my hand-held pressure gauges use? Measured the male thread to 0.54"; is that 9/16 (=0.5625)? Asking as I'll probably need the 1/4 female to 9/16 male adapter.

[dwhitlow]

I'm not after amazing absolute accuracy, but would like to know within a few percent, especially for bailouts.

Why?

For bailouts, which you may never need, forget precision when you mix. Just make sure the analyser works and you know what the gas actually is.

I recently checked the 10 year old gas in some of my bailouts. It is still a useful mix so I've refreshed the label.

[Wibs]

Why?

For bailouts, which you may never need, forget precision when you mix. Just make sure the analyser works and you know what the gas actually is.

I recently checked the 10 year old gas in some of my bailouts. It is still a useful mix so I've refreshed the label.

As in I want to know if it's 230 bar, 200 bar or 170 bar. My current gauge definitely reads lower, but now I'm beginning to doubt them all!
Deeper and longer chews through gas with bailout being the main bottom time constraint. Yes, there's the shot line with other divers gas, but "what if" the bailout meant loosing the shot too?

Just prudence really.

[dwhitlow]

As in I want to know if it's 230 bar, 200 bar or 170 bar.

Why stress? If you look after kit, check things that matter, and have a bit of luck, you'll never need it.... 12 years since my last bailout and I'm staying hopeful....

If you do need bailout the important check is that the gauge doesn't show gas when it is actually empty. After all, unless you've been very unlucky, when the gauge says you've run out the surface shouldn't be far away. Possibly bent is better than drowning, and possibly bent is usually not bent, and even a bit bent is usually repairable. Drowning tends to be a lot more binary.

My current gauge definitely reads lower, but now I'm beginning to doubt them all!

A gauge that reads lower is fine. A gauge that read high (i.e. not empty when empty) should be destroyed.

Deeper and longer chews through gas with bailout being the main bottom time constraint. Yes, there's the shot line with other divers gas, but "what if" the bailout meant loosing the shot too?

So what? I can imagine lots of horrid things in the future an mostly they don't happen.

Living life in the world of 'what if' is a terrible idea. It's like being trapped in a crazy movie where you are being forced to deal with your worst imaginings!

IMHO just enjoy the moment, be fairly sensible, deal with obvious stuff, and make the most of what you can see...

[graham_hk]

Use the same gauge for all parts of the filling and you’ll get way better results … I can fill using a scuba spg and nail the mixes but when I use multiple gauges (even expensive /accurate) it takes a while to learn the peculiarities and get dialed in. But at the end of the day - you’re in a rebreather - it doesn’t matter

[N Bailey]

Another yes for Undersea