"We had to take down our compressor due to a leak."

[kr2y5]

A couple of days ago, LDS told me that they had to take their compressor down because they found a bad smell and some oily residue, and needed to change the filters. My tanks probably were not affected, as I've been getting fills elsewhere for a couple of weeks prior to stopping by, but it did make me wonder: if I were one of the customers, whose tanks may have been getting filled during the time their compressor had a leak, and considering that I tend to often get partial-pressure Nitrox blends in the very same tanks, what would my options be upon hearing such news?

As far as I can tell, there is no such thing as a test for hydrocarbons (or is there one?). Even if I decided to inspect the tanks and use the UV light, or whatever, that would not guarantee that I would catch traces of synthetic oil. What, then, would be the course of action: have the tanks O2 cleaned? The impression that I got from reading various threads here and there is that, such compressor issues are not very uncommon (or are they?), and yet, the prospect of the shop calling all their recent customers to have them O2 clean their tanks every time a such issue happens, like a CDC center calling airline passengers following a virus outbreak, seems pretty impractical.

So, how often does this happen, what's the risk, and the optimal course of action?

 

[The Chairman]

There are tests for hydrocarbons, but in reality, the CO analyzers will pick this up if you ever do partial pressure blending. Me? I won't allow PP Blending in any of my tanks. I've had CO poisoning before and didn't like it. Membranes, banked and mix on the fly are fine. Just not PP.

 

[Got2Go]

So, how often does this happen, what's the risk, and the optimal course of action?

It should never happen, if proper maintenance is followed on the compressor and filter stack.
But if it happens, the issue should be fixed before filling any tanks for diving purposes, and a new sample sent in for analysis.

Any air that smells automatically fails the Grade E specification (and others), regardless of any other traces analyzed to be within the specification.

The safe thing to do is have the tanks/valves/regulators cleaned.

 

[NAM001]

kr2y5... what is the leak you referenced? the only leak I can imagine is a air leak and that should not smell. At least not as far as the air in the tank goes.

 

[kr2y5]

kr2y5... what is the leak you referenced? the only leak I can imagine is a air leak and that should not smell. At least not as far as the air in the tank goes.

I haven't asked about the details, all I remember is a mention of smell, oil residue, leak, filters getting replaced, and compressor being back in business within a day or two. Maybe I mixed something up. I guess that brings the question: what are the failure modes of a compressor, with respect to contaminating tanks with hydrocarbons?

 

[clownfishsydney]

As others have pointed out, this is normally casued by trying to get too many hours out of your filters. Should never happen if you keep track of fills done since last repacking filters.

 

[The Chairman]

this is normally casued by

Normally? Sure. However, I've known of at least two stack failures within a few days of replacement and at least one that had not gone half of it's rated hours. Caca occurs even to the best of shops.

 

[clownfishsydney]

The word I used was "normally".

 

[Mahoney86]

I didn't think this was very common up until recently. I had 3 tanks come back loaded with oily residue and are now shot. Im seeing your post and have talked to some others and it seems like this is becoming a bit more common. What scares me is that I have 7 tanks, my previous LDS has now went out of business and they did hydro and VIP on all of them last year. 3 out of the 7 were junk this year. The only thing I can think of is the 3 bad ones were nitrox blends so maybe that was part of the issue. Though now I am a bit worried, if this happens in the middle of the dive season, other then doing another VIP how can I ever know if I have oil or something bad in my tank from a fill?

 

[tbone1004]

bunch of failures, but if they blew hydrocarbons into your tanks, they should be offering to o2 clean your tanks/valves and regulators for free