Reg Service

[b1gcountry]

I have yet to see a first stage where the seat rests on the orifice when the reg is depressurized.

I have not either. All my regs are designed so the seat rests off the orifice w/o pressure. I think I recall some first stages using a normally closed HP seat, but I may be mistaken. Not servicing a large range of regs I mostly know about my own.

It makes sense as well as if the orifice rested on the seat in any first stage design, absolutely nothing would happen when you turned on the tank valve.

Just because a reg is normally closed, however does not mean it will not open when pressure is applied. Thinking it through, you may have problems balancing it though.

Of those that don't, balanced regs will experience less set over time as the spring pressure is much lighter in the balanced design.

Much lighter, but only when the reg is depressurized, right? I never really though of this. That may be the first real advantage I've ever heard of for using a balanced second stage.

Tom

 

[Rick Inman]

Second stages vary. Some use a system with an air chamber designed to ensure their is no spring pressure to force the poppet against the orifice when they are bepressurized. Others use a mechanical switch or key to depress the purge valve to accomplish the same effect by lifting the seat off the orifice in a much less mechanically complex fashion.

Atomics, being one of them.

 

[DA Aquamaster]

Much lighter, but only when the reg is depressurized, right? I never really though of this. That may be the first real advantage I've ever heard of for using a balanced second stage.

Yes. When the reg is pressurized the downstream force of the gas coming through the orifice is counteracted by either spring pressure (unbalanced poppet design) or a combination of (lighter) spring pressure and air pressure acting on the otehr end of the poppet from the balance chamber side.

In my experience with otherwise identical regulators (the Scubapro R109 "Adjustable" and the R156 "Balanced Adjustable") I always got longer second stage seat life in the balanced second stage due to the lighter spring pressure. I think my experience was typical as Scubapro back in the day when the R109 was their top of the line second stage included one of two types of keys to keep the purge depressed and carried this practice over to the Pilot valved "Pilot" and the center blanced "Air 1". However it was discontinued with the R156 and the plastic cased version of that reg, the G250. By then the keys had also disappeared on the Air 1 replacements - the D300, D350 and D400 as they were never needed due to the very light springs used. For a while however Scubapro continued to use a switch on the purge cover on some unbalanced models such as the R380 to depress the purge and reduce seat engraving during storage. So I gather from those trends that seat engraving was (is) a bigger problem with unbalnced second stage than it was(is) with balanced second stages.

Scubapro also experimented with an a pneumatic system in the early S600 that removed all spring pressure when the reg was depressurized. This worked fine, but was regarded as being overly complex and, potentially at least, caused more problems than it resolved as the greater complexity created potential failure modes that outweighed the benefiits of reduced seat engraving that was already a non-problem in a balanced designed that was serviced annually.

 

[james croft]

Lots of good advice given. I service my own regs and sometimes go for years before tearing one down. Never had a problem, but I keep water out the first stage and soak my regs well in fresh water with a pony on them under pressure. I keep an eye on my IP to make sure it isn't creeping, etc. I've seen some of the prices charged by shops to service a reg and it is sometimes more than the reg can be bought on eBay.

 

[deepblueme]

DA is right on the money about the way air pressure and spring pressure both balanced and un balanced work.

The service time on your regs is up to you but like I told my customers
"Your reg is life support equipment for a hostile enviroment you are not intended to be in other wise you would have gills."

Ive seen reg systems go 10years between service and be fine (one of my SP Pilots) and others...

As far as getting water in your first stage. Most 1st let water in thru the amb. ports and that is where you see most problems. Other than the sealed diaphrams or Sherwoods
Salt water thru the filter turns it green and kills your spg. Same with fresh but with out the green filter part.

 

[dave4868]

Lots of good advice given. I service my own regs and sometimes go for years before tearing one down. Never had a problem, but I keep water out the first stage and soak my regs well in fresh water with a pony on them under pressure. I keep an eye on my IP to make sure it isn't creeping, etc. I've seen some of the prices charged by shops to service a reg and it is sometimes more than the reg can be bought on eBay.

Same here, long periods before overhauls are actually needed. (Sherwoods.)

I have a question for anyone: Are some designs significantly more finicky and require more frequent overhauls than others?

What kind of regulator does the OP have and what's he really gaining by staying with the "maintenance agreement"?

"Life support" piece of mind or something more real?

Dave C

 

[b1gcountry]

The service time on your regs is up to you but like I told my customers
"Your reg is life support equipment for a hostile enviroment you are not intended to be in other wise you would have gills."

I hate this statement. It is a valid, up to a point, but I've seen it used too many times by jerks trying to sell some uneducated new diver some overpriced piece of crap that they don't need. If there is one concept the Scuba industry has abused more than any other it is the idea that since our ability to breathe depends on the equipment they manufacture and sell, that they are justified taking any amount of our money. "Isn't your life worth the extra $500?" Actually, my life is worth a lot more, but that reg is not.

Tom

PS-I'm not saying deepblueme had this intention at all, I just have this rant about some other folks I've had dealings with in the past.

 

[scubafanatic]

...one thing to consider, however, is that there is a fair chance you will take a perfectly decently performing reg in for annual service and have it come back screwed up....I presently have an Atomic B1 (upgraded with the B2 piston) that was serviced last year and was messed up..... IP low @ 110-115 psi, among other things, had that fixed by a 2nd shop, appeared OK hooked to a tank, but fell short again on a spendy dive trip, so I'm now trying to figure out who else to have look at it...and the reg was working great prior to the service, but I figured it could use an annual as it had been maybe 18 months/100 dives since last service...sigh.

Karl

 

[300bar]

...one thing to consider, however, is that there is a fair chance you will take a perfectly decently performing reg in for annual service and have it come back screwed up....I presently have an Atomic B1 (upgraded with the B2 piston) that was serviced last year and was messed up..... IP low @ 110-115 psi, among other things, had that fixed by a 2nd shop, appeared OK hooked to a tank, but fell short again on a spendy dive trip, so I'm now trying to figure out who else to have look at it...and the reg was working great prior to the service, but I figured it could use an annual as it had been maybe 18 months/100 dives since last service...sigh.

Karl

Can't completly be sure,since I can't see your reg.and it's very unlikely you'll stop by and show me
But it sounds like that when they did the upgrade they forgot to put in the shimms from your old piston up to the new one.That should be the reason the IP is low.

Don't have the shimm colorcodes with me but any Atomics dealer can tell/sell you the right shimms ,to rease the IP.


cheers,
Evert

 

[DA Aquamaster]

...one thing to consider, however, is that there is a fair chance you will take a perfectly decently performing reg in for annual service and have it come back screwed up....

The same thing applies to annual aircraft inspections. A lot of parts get messed with and it only takes one small error to cause problems. Over the years I have discovered a few post annual inspection problems - the pre-flight discovery that the aileron cables reversed on a V-35 Bonanza (I had to look about 3 times to really believe what I was seeing, rather than what I expected to see), an inflight trim problem on a Cherokee, a short and semi-exciting flight, and the in flight loss of oil pressure in a Seneca due to a tool being left on top of the oil cooler resulting in a precautionary landing on one engine - and a priceless "oh my God I can't believe I did that" look of horror on the face of the mechanic when we removed the cowling and saw the cause of the problem.

Regulators are less complex with a lot less to go wrong and the most common failures tend to be open failures resulting in very minor to large free flows rather than a failure to deliver gas, but it is still worth a thorough pre-dive check and it does not hurt to have service work done well in advance of a major trip to ensure any minor probems occur on a local dive where the local shop can make any adjustments required without ruining your $2000 dive trip.