Valve Service Question

[Griffo]

So I've just completed the TDI O2 Service Tech course which certifies you to clean gear for O2 service (nothing unexpected in the course really) including tanks and valves. As the owner of a large number of tanks and valves already (and growing) and as we have to Hyrdro our stuff every single year here, I expect to save a fair whack of $$ doing it myself.

However, on the course they taught us to replace everything in the valve every service - to change the burst disks and the bonnets etc every service. I've noticed however that many of the service kits seem to have these as optional parts. So.. do people really change everything every service or not? Looking at the kit prices it takes the price of a kit from say $15 (cheaper if I sourced the o-rings directly I assume) to say $35 for an all inclusive kit.

Just looking for real-world advice vs theoretical course info

 

[dumpsterDiver]

I would change nothing in the valve unless there was a problem. If you want to be good, take apart and replace the stem O-ring, re-lube and assemble.. cost: 1 o-ring and lube..

 

[Bob DBF]

I'm with dumpsterDiver when dealing with my valves. My old steel 72's will get a new burst disk after the hydro if it's a new acquisition. If I was working with O2 partial pressure blending and I did not have complete control of the valves use, I would do a complete clean and rebuild, but I'm kind of skittish around pure HP O2.



Bob
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I may be old, but I'm not dead yet.

 

[flots am]

However, on the course they taught us to replace everything in the valve every service - to change the burst disks and the bonnets etc every service. I've noticed however that many of the service kits seem to have these as optional parts. So.. do people really change everything every service or not? Looking at the kit prices it takes the price of a kit from say $15 (cheaper if I sourced the o-rings directly I assume) to say $35 for an all inclusive kit.

Just looking for real-world advice vs theoretical course info

Like everything else, "it depends"

I have the valve service done and the burst disk replaced when the tank gets hydro'd, because hydro is every 5 years here, and I don't trust a burst disk to last 10+ years.

If you need a hydro every year, I certainly wouldn't be changing the disk every year.

 

[Griffo]

Thanks. I should have stated that a lot of my fills will be PP blending so there's a lot of pure O2 going through these things.

 

[divingtactics]

I buy all my valve parts from Northeast Scuba Supply as individual parts and I do tend to replace most things with each service. Copper crush washers can be reused once by putting them on a flat surface with some 400 grit wet and dry on the base and just moving the washer back and forth till the grooves are sanded out both sides. Bonnet nuts, I reuse, stems I reuse but that's about it. Burst discs, I tend to replace each time along with all o-rings and seats. The most important thing for you to replace is actually the seat, as the material is standard nylon and it can combust if you open a valve too quickly while dealing with 100% oxygen. Of course, all lubricants should also be oxygen safe too.