Should port o-rings be changed during overhaul?

[wKkaY]

This past year I got two regs serviced (by different shops) and both returned them without port o-rings replaced. Some of them looked rather frayed too.

Is it customary for a dive shop to replace them all, or only replace damaged ones, or?

 

[JackD342]

When following manufacturer direction and using manufacturer service kits, there are some brands that do not include static o-rings in the kits and say to only replace them as needed.

That was the norm for Oceanic brands before Huish, I don’t know if it has since changed or not. Sherwood/Genesis also re-uses o-rings. Aqualung/Apeks, Mares, and Cressi replace all o-rings. I don’t personally know other brands.

 

[lexvil]

I rarely bother for my own use but if paying for service and they come in the kit they probably should be.

 

[shurite7]

When learning to service regs one instructor stated something similar already written above, static o-rings were not changed while dynamic o-rings were changed annually. Several old timers have told me the same thing. It is now, at least with Scubapro, Aqualung, and Apeks (I can't speak for any others), recommended that all o-rings should be replaced. With that being stated, I know of some service kits for older regs, supplied by the manufacture, do not come with static o-rings.

Don't forget to change the o-ring in the QD.

 

[The Chairman]

Not changing them is sheer laziness in my estimation. #010 for the LPs and #012 for the HPs. It might take 15 seconds if you're in a slow mood.

 

[tbone1004]

Poseidon comes with all o-rings and it is called out to replace them all, IIRC Apeks calls out to replace and they definitely are included.
The ones on the hoses should obviously be changed at service as well, though the second stage end and spool o-rings are not included in the kits. Anything less than replacing all of them like @The Chairman said is sheer laziness

 

[spoolin01]

Carry a few 010, 011, 012 o-rings in your dive kit to cover most LP/HP hose needs. As you noted they can become quite frayed from use.

 

[Fibonacci]

One thing has always OCD-niggled-me about SCUBA LP and HP port o-rings

From what I can see detailed in specification charts:
LP port is 3/8" x 24 UNF SAE -3 O-Ring Boss (ORB)
This should take a AS568 -903 70A o-ring (ID 7.65 x 1.63mm) but 'everyone' uses a -011 5/16" x 1/16" (ID 7.65 x 1.78mm)
Pretty close.

HP port is 7/16" x 20 UNF SAE -4 ORB
This should take a AS568 -904 90A o-ring (ID 8.92 x 1.83mm) but 'everyone' uses a -012 3/8" x 1/16" (ID 9.25 x 1.78mm)
Not close!

So why aren't the 'correct' -900 series o-rings being used?
Convenience?

 

[spoolin01]

Interesting observation! From what I can tell Dacor used 903 and 904, and 905 for 1/2" ports. All were harder than the common 70D.

 

[Oldenboldiver]

With few dishonorable exceptions, most genuine manufacturers' service kits come with new o rings for all ports.

In the few cases where they are not included I would still expect a reputable service technician to replace them anyway from the stock of o rings they should have to hand.

Not replacing them is being a cheapskate and what little saving in time/money is more than lost when the customer brings the regulator back for a leaking port.