Disclaimer: I’m not a certified technician. This is how I service my own gear. Always follow your manufacturer’s instructions and seek professional service if you’re unsure.
Servicing your inflator cartridges is a quick way to keep your gear running smoothly, whether you’re diving a Fathom Gemini MAV or a standard K-style inflator. This guide shows how I service my own equipment using the Power Inflator Tool, fresh O-rings, and oxygen-compatible materials.
Tools and Materials
Everything shown here is oxygen-clean, and gloves are worn during the entire process to prevent contamination.
- Fathom Gemini MAV (or any K-style inflator)
- Power Inflator Tool
- Flathead screwdriver
- O-ring pick
- Microfiber cloths
- O₂-compatible lubricant (Tribolube, Christo-Lube, etc.)
- Replacement O-rings (Gemini service kit or manufacturer-specified sizes)
- Clean gloves
Step 1 — Remove the Inflator Cartridge
Use the Power Inflator Tool to loosen and remove the cartridge from the MAV.
It should come out smoothly without high torque.
Step 2 — Remove the Outer O-Rings
Take off and discard the two large O-rings with an O-ring pick.
Step 3 — Clean the Cartridge Body
Wipe the exterior with a clean microfiber cloth.
Remove old lubricant and any debris so the O-rings will seat correctly later.
Step 4 — Disassemble the Inner Section
Hold the inflator button firmly to prevent internal movement.
Use a flathead screwdriver to remove the inner retainer screw from the top of the cartridge.
Step 5 — Remove the Small O-Rings
Brass O-ring pick might work better to remove the small internal O-rings.
Brass is soft enough to avoid scratching aluminum or stainless components.
Work slowly and avoid digging into the metal.
Step 6 — Clean Internal Components
Wipe each part with a dry microfiber cloth.
Inspect for wear or damage as you go.
Step 7 — Install New Small O-Rings
Lightly lubricate new O-rings with an oxygen-compatible grease.
Use a nylon pick to guide them into place without overstretching or twisting.
A thin, even film of lubricant is enough.
Step 8 — Reassemble the Cartridge
Rebuild the internal assembly in reverse order.
Seat the retainer screw firmly but do not overtighten. The O-rings provide the seal, not torque.
Step 9 — Install New Large O-Rings
Lubricate the large O-rings with a small amount of O₂-compatible grease.
Install them into their grooves.
Step 10 — Reinstall the Cartridge into the MAV
Thread the cartridge back into the MAV by hand until seated.
Stop when snug—over-tightening can deform O-rings or make future service difficult.
Repeat the same process for the second cartridge.
Servicing a Standard K-Style Inflator
The same method applies to a typical BCD inflator:
- Remove the cartridge
- Replace internal and external O-rings
- Clean parts
- Lubricate lightly
- Reassemble
- Reinstall
Why Regular Inflator Service Matters
Inflator cartridges rely on small O-rings and smooth internal movement.
Replacing worn seals helps prevent:
- sticking inflator buttons
- slow leaks
- uneven gas delivery
- contamination inside the valve body
Whether you dive open circuit or a rebreather, a few minutes on the bench can extend the life of your equipment and help keep it working predictably.
Related Products
A compact, machined-aluminum tool designed for recessed inflator cartridges on Fathom MAVs and all standard K-style inflators. Simple, reliable, and built for the job.