I wish my pressure gauge didn't lie to me...

[charlesml3]

Hi gang,

I took my reg in for an annual and while we were standing there, I asked the guy to connect it up to a known pressure because I thought my computer was reading low. Before he even connected it, he said "Yep, it's going to read 150 pounds or so low." Turns out, it's reading 220 pounds low at 3000, 2000, 1000 and 700 pounds of tank pressure.

Now before someone jumps all over me, I KNOW. It's a "safety thing" that the manufacturer does on purpose. I just find it a bit annoying. I'd rather have ACCURATE information. I wonder if my depth gauge reads deeper than actual as another safety measure

Besides, now that I know it's reading 220 low, I'm just going to figure that offset into my turn pressure.

-Charles

 

[charlesml3]

Whoops. Sorry about the triple post.... Browser freaked out...

 

[J.R.]

Besides, now that I know it's reading 220 low, I'm just going to figure that offset into my turn pressure.

-Charles

Your choice I suppose. But if its reading 220 lb low at 3000 that means you actually have 3220... at 500 ya' got 722... you STILL get your full allotment of air... but with a 220 lb. 'cushion' (kinda' like the ol' J-valve thing... without the J-valve)...

Is the few minutes ya' get on the 220 worth it???

 

[charlesml3]

It's not about whether or not anything is "worth it." I just wish the data I was getting from my computer was ACCURATE. I don't want or need anything lying to me, even if it's supposed to be safer. I can make better decisions with accurate information.

I now feel bad about giving my dive op a hard time about consistent "short fills" when in fact, the tanks were full. It was just my computer shorting it as a "feature."

-Charles

 

[J.R.]

It's not about whether or not anything is "worth it." I just wish the data I was getting from my computer was ACCURATE. I don't want or need anything lying to me, even if it's supposed to be safer. I can make better decisions with accurate information.

I now feel bad about giving my dive op a hard time about consistent "short fills" when in fact, the tanks were full. It was just my computer shorting it as a "feature."

-Charles

??? If your guage is reading 220 pounds LESS than what is actually there... and you're still showing a short fill... wouldn't it be 'shorter'... i.e., if your guage reads a 2700 lb fill... you'd ACTUALLY have 2480 lb... THAT would be a really short fill...

... go ahead... complain...

 

[MSilvia]

Check your math J.R.

 

[MauiScubaSteve]

I've noticed this buffer even with analog guages. I have a couple really old SPG's with no other markings than made in italy. My employer has Aqualung consoles on all the rental gear, and all these newer SPG's read at least 200psi lower than my old ones.

 

[fisherdvm]

I think most scuba equipment errs on giving you too much air, than too little. As all gauges and meters require recalibration eventually, they are engineered to err on the side of safety. We discussed about metal fatigue and other aspects of the SPG, and it was my understanding is that they tend to under read the pressure (get you out of the water safely), rather than over read your pressure.

It is kinda why when you have a problem with your regs, they tend to free flow, rather than shut down.

 

[J.R.]

Check your math J.R.

DOH!!!!

NEVER MIND!!!

 

[FIXXERVI6]

Just another reason to avoid AI computers

Older SPG's were not as accurate so there was a window there, the newer tube type SPG's are far more accurate, I'm sure someone else on the board with more history can elaborate more.

My SPG has always been fairly accurate, within 50-75 psi or so, and on a gauge that goes to 5000 thats pretty durn good.