Tusa First stage failure.

[Brendo_111]

Hi

I was diving on the weekend, when i put my first stage on the tank and cracked it to see the pressure my regs started free flowing, I shut it off thinking it was just in need of adjustment. After i adjusted it, it settled down and was fine untill I descended where I noticed that it was now my occy free flowing, but wasnt too bad I swapped my primary and occy over and same thing, unused reg still free flowing.

I took it to the dive store and turns out my first stage had failed and was over pressurizing my regs. I was going to get it checked out to see what the cause is/was, but in truth it has my confidence in the failed unit shaken. The unit is near new condition, only 7 dives old and had it serviced 6 months ago.

I was mainly going to ask is this unheard of for a first stage to break/free flow? If so what could have caused it? I always methodically wash my regs and all gear in the laundry sink after every dive and ensure their dry before storage.

 

[keyshunter]

Definitely not unheard of, especially after a fresh service. If the shop you took it to was the one who serviced it and they did a complete rebuild, I am surprised that they did not offer to repair it at no charge.

 

[Jim Lapenta]

Why was it serviced? What exactly was done. What did you adjust? The second stages or the first stage? Unless you are a tech there is no adjusting a first stage. It sounds like the HP seat failed in the 1st. Is this a piston or diaphragm reg. a seat failing is not unheard of. Washing/rinsing is not going to keep a 1st from failing. HP seats are consumables. They are a soft material. Not installing them correctly can cause premature failure. Was it ok the last time you used it before getting it serviced? There's really not enough info to say why it failed for sure. I'd have a good tech rebuild it and test it thoroughly. I've started testing all regs I service for a couple hours in the pool as well as on the bench.

 

[redacted]

There is not a regulator made that could not suffer from such a problem nor is there a regulator on the market that has a clear propensity for such problems. I would suggest that knowledge will get you a lot more real confidence than unnecessarily spending $$$.

Manufacturing defects and service errors just can not be 100% eliminated.

 

[ams511]

Tabata is a well-respected manufacturer which is a supplier to Scubapro. Many of the models TUSA sells are the same as a Scubapro with minor cosmetic differences. I would not lose confidence in the first stage but I would lose confidence in the dive shop that serviced it. Without seeing the regulator I am guessing that you have IP creep which is causing the second stages to free flow. This could be do to a bad seat or o-ring, neither of which is a major problem.

If the regulator has only 7 dives on it then why was it serviced? Also you may want to invest in an IP gauge so you can check the IP yourself before a dive.

 

[Brendo_111]

Why was it serviced? What exactly was done. What did you adjust? The second stages or the first stage? Unless you are a tech there is no adjusting a first stage. It sounds like the HP seat failed in the 1st. Is this a piston or diaphragm reg. a seat failing is not unheard of. Washing/rinsing is not going to keep a 1st from failing. HP seats are consumables. They are a soft material. Not installing them correctly can cause premature failure. Was it ok the last time you used it before getting it serviced? There's really not enough info to say why it failed for sure. I'd have a good tech rebuild it and test it thoroughly. I've started testing all regs I service for a couple hours in the pool as well as on the bench.

I had it serviced as it had been more like 10 months instead of 6 since i last used it, since then ive done 7 dives with it this summer and on this dive it had the problem.

For the service I just took it to the shop and said "can you service this please" and they did a full one so i have put my faith in the dive shop to do the right thing, which i strongly believe they did. i have taken it to another shop and im waiting for the verdict.

What kind of service intervals are we talking for the regs? 50 dives.. 100...? or is it time period, 6 months 12 months etc?

---------- Post added April 9th, 2015 at 09:45 AM ----------

Tabata is a well-respected manufacturer which is a supplier to Scubapro. Many of the models TUSA sells are the same as a Scubapro with minor cosmetic differences. I would not lose confidence in the first stage but I would lose confidence in the dive shop that serviced it. Without seeing the regulator I am guessing that you have IP creep which is causing the second stages to free flow. This could be do to a bad seat or o-ring, neither of which is a major problem.

If the regulator has only 7 dives on it then why was it serviced? Also you may want to invest in an IP gauge so you can check the IP yourself before a dive.

Whats IP creep? Inlet pressure?

Yeh ive taken it to a different shop now waiting for the results.

I am very happy with my TUSA regs (RS-510) and other TUSA stuff, they have been great and always easy to breathe with just this incident has my faith shaken in it though. Im keen to wait for the analysis on what went wrong, i was just wondering if im unlucky or if it was something i did...

 

[jwelburn]

I've seen an inordinate number of those first stages with wild IPs come through the door (Intermediate Pressure, which is how much pressure is being supplied to the second stages). All from a rental fleet, but not too long after being added to the fleet, and at much higher rates than the mk11/17s that make up the rest of the fleet which are all much older.

 

[ams511]

Whats IP creep? Inlet pressure?

Yeh ive taken it to a different shop now waiting for the results.

I am very happy with my TUSA regs (RS-510) and other TUSA stuff, they have been great and always easy to breathe with just this incident has my faith shaken in it though. Im keen to wait for the analysis on what went wrong, i was just wondering if im unlucky or if it was something i did...

Single hose regulators are a 2-stage design. The first stage reduces the tank pressure to 135 PSI +/- 10 psi over ambient pressure, the second stage further reduces the pressure to ambient. With IP creep the first stage reduces the tank pressure to normal intermediate pressure but then it increases over a short time period. At some point the intermediate pressure is high enough to start the second stages free-flowing. You can monitor this with an IP pressure gauge that attaches to the quick connect of your LP inflater hose.

If your regulators started to free-flow after 1 to 3 dives I would have said it was probably an adjustment issue as the seats broke in, but seven dives seems a bit long for the seats to break in.

Most regulator manufacturers have more or less standardized on a 2-year (100 dive) rebuild cycle with a check in the off year. Some have even longer service intervals. Most DIYers rebuild when they notice the IP starting to climb or a drop in performance.