Hi Dave,
Well, I have a different opinion on how often to service regulators.
I am not a believer on doing any service that is only based on time interval or number of dives, without some reasoning (or justification) behind it. Preferably, the decision to schedule maintenance is based on some actual observation or other technical, engineering, scientific, or logistics reason behind it.
We are used to changing the oil in our vehicle engines on a regular interval (based on mileage or hours for other engines), but oil breakdown and engine wear is somewhat predictable. Even then, we don’t totally rebuild the engine on a regular interval.
Preventive maintenance and complete rebuilt are two different subjects. I have a hard time thinking of any other equipment were we would do a complete rebuilt on a regular basis.
I am sure you are aware that a very large number of regulator failures occur right after service or when the equipment is new. This is due to what we call “infant mortality” (that is part of the reason we see a year warranty offered on many products). Infant mortality is caused by a number of reasons (new unproven parts working together for the first time, human error, etc).
That is why I am a strong believer on: If it ain’t broke, don’t fix it.
In other words don’t disturb a good working machinery… it doesn’t like it.
dhaas wrote:
I go by number of trips whether one week in the Caribbean or Pacific trip where close to 50 dives can be done on a trip. After about 4-5 good salt water trips no matter how carefully I rinse / soak my regulator (we're talking single hose here)
it's due.
David Haas
http://www.haasimages.com
Can I ask you how did you come up to this conclusion? Have you notice actual physical evidence? If you have notice any sign of corrosion, that is a good indicator for service.
I bet your cameras don’t need to be serviced or rebuilt as often… you probably take better care of them…
Just kidding.
Note: I should point out that I am not a reliability or maintainability engineering expert or anything similar. I just have somewhat of a working knowledge of the subject. Terms like Mean time between Failure (MTBF), Objective Quality Evidence (OQE), Infant mortality (as it applies to equipment and machinery), End of Life Failures, “Bathtub curve Failure distribution”, and a few others acronyms, are commonly used in what I do.
The pneumatically balanced second stage has a much lighter mechanical spring. When the regulator is not being used (not pressurized), it is only the spring force holding the soft seat against the volcano orifice. In a conventional downstream demand valve, that spring force is stronger and therefore the seat will normally engrave sooner.
Some regulators are more sensitive than other to the amount of engraving on the LP seat. For example, the Argonaut (DH regulator) second stage can be deeply engraved and still performed just great due to the second stage geometry and the mechanical advantage of the large diaphragm. Most single hose demand valves require more attention.