My compressor and fill panel setup (updated)

Not a lot has changed with my compressor setup. I’m still running my Alkin W31 compressor and have about 250 hours on it. I bought it brand new in mid-2019. So far the only maintenance I’ve done is regular oil changes and filter changes.

Full disclosure: I did have 2 issues. The 240v to 12v transformer on mine failed (broken wiring/ bad contact) but Alkin shipped me a new one overnight. Also the pneumatic valve on my autodrain was sticking closed but that’s more general maintenance. It was very easy to service myself. Aydin at Alkin W31 was super responsive. Sent me instructions and walked me through everything although it was all pretty self explanatory.

Based on hours I pump about 12,000-13,000cu/ft of nitrox 32 a year through it with a blending stick. Not a whole lot compared to most dive shops but it has treated me well. I almost never pump air as almost all of my local diving is on a rebreather or 32%.

One last thing I will say is their hours rating on their filter cartridge is a little bogus. I think it says something like 50 hours in the manual. It’s a small P21 type cartridge which Bauer rates for something like 10 hours at 20c/68f. You should be changing this out every ~10-20 hours depending on temperature / humidity. I’m not sure where they got the 50 hour number from. I also added a larger secondary filter stack to my compressor as I wanted to make sure I was pumping very dry and clean air.

Although the Alkin comes with a repackable filter cartridge and you can save money by refilling with your own 13X + Activated Carbon + Hopcalite I use third party cartridges from FilterTechs. I just find it easier and saves me time. I hated repacking their filter.

Bauer Breathing Air Filter W5-9183 X22249

Bauer Cleaning Air Filter 057679410, X22629
I use the X22629 cartridge as my secondary filter stack already has Hopcalite in it so that my primary filter functions more as a dryer but if I didn’t have a secondary filter then I’d probably recommend using the X22249.

My panel is kind of messy but this is the general layout. Nitrox Stick goes into compressor air intake. It’s 1′ diameter hose which I have kept as short as possible to minimize resistance.

Compressor Output -> Check Valve -> 10″ (P31) Secondary Filter Stack -> Bleeder -> Priority Valve (set to 2200psi) -> 5 port manifold > 2-3 DIN Whips or 2 DIN Whips and Secondary O2 Analyzer with DiveSoft flowmeter.

Everything is using Parker QC fittings so I can unplug and move things around. Same fittings I also use on my booster.

So what have I learned since 2019? Well I learned compressors are not rocket science. Dive shops would like you to think they’re magic and run on fairy dust. The reality is anyone with a modicum of mechanical ability and common sense can use and operate one. I’m nowhere close to being an expert with any of this and obviously people have been doing this far longer than me.

I’ve owned my compressor for 4 years and it was the best thing I ever did for my diving. I’ll never go back to not owning a compressor. I wish I had bought one sooner. No sitting in traffic, worrying about hot fills, worrying if your tanks just sat in the corner and forgotten about. You fill on your own time and you know it gets done right. It’s an incredible time saver.

If I had to go back and do it all over again I probably would have bought a 5cfm or larger compressor. The 3.6cfm works well for my needs but it can be quite slow and painful when you have to fill multiple sets of doubles at the end of the day. Having said that, it still saves me time since I do not have to leave my house

I have tested my gas quality twice a year initially at the end of my estimated filter life cycle and I’m still producing Oxygen Compatible (Modified Grade E) air.