The shipping case arrives
The iQSub FX CCR ships in a large, waterproof hard case — the same type of rugged roller case used to transport sensitive dive equipment safely. The carbon-fibre oxygen cylinder and tools arrive alongside it, wrapped in protective plastic.
Opening the case
Everything is neatly packed and individually bagged in heavy-duty plastic. The FX CCR bag, breathing loop, scrubber assembly, electronics, and accessories are all present. Time to inventory every item before starting assembly.
Full kit laid out
Everything unpacked and laid out: the FX CCR soft bag with integrated counterlungs, the white polypropylene scrubber canister, corrugated breathing hoses, blue oxygen hoses with MAVs (Manual Addition Valves), Shearwater primary handset, battery packs, carbon-fibre oxygen cylinder with valve, O2 sensor pod, and all the O-ring and hardware accessories. The BOV is part of the full kit but not pictured here.
Inspecting the sensor head
The FX CCR head unit is opened for the first time. The three galvanic oxygen cell sockets are visible, along with the solenoid wiring and the blue oxygen injection hoses. The oxygen The oxygen MAV — labelled OXYGEN — and the diluent MAV are both clearly identifiable.
Dating the O2 sensors
Before installation, each galvanic oxygen cell is dated with a permanent marker. The Narked@90 cells used here carry a calibration label — writing today's date ensures the sensor replacement schedule can be tracked accurately. O2 cells typically need replacing every 12–18 months.
Installing the O2 sensors
The dated O2 cells are carefully seated into the head unit. The FX CCR uses three sensors for voting logic — the electronics compare all three readings and alert if one diverges, providing redundancy critical for safe CCR diving.
Preparing the battery canisters
The FX CCR runs on two 18650 lithium-ion cells per canister. The cells slide into the waterproof battery tube, which is then sealed with threaded end-caps. The canister threads into the head unit to power the solenoid, electronics, and handset.
Packing the scrubber
The scrubber canister is filled with sofnolime — a calcium hydroxide-based CO2 absorbent. The granules are poured around the central standpipe and gently tapped to ensure an even, compact fill with no voids. Proper packing is critical to prevent channelling that could allow CO2 to bypass the scrubber.
Closing the scrubber canister
The top diffuser plate — a radial grid that distributes gas flow evenly across the scrubber bed — is pressed firmly onto the packed canister. This ensures consistent gas flow through the sofnolime on every breath.
Mating the head to the scrubber
The sensor head is placed onto the scrubber canister. The labelled connector block is clearly visible: HUD, PRIMARY, and BATTERY ports — for the heads-up display, primary handset (Shearwater), and battery canister respectively. The head seats and locks into the canister body.
Connecting the gas supplies
The carbon-fibre oxygen cylinder is connected to the head unit. Diluent is not carried on-board — it is added externally via the QC6 connector on the diluent MAV. The blue oxygen hoses are routed carefully to avoid pinching. The bright yellow-green lanyard is threaded through the designated slot in the scrubber canister, securing the head unit so it cannot accidentally come apart during a dive.
Plugging in the handsets
The Shearwater handset and HUD connectors are plugged into the labelled ports on the FX CCR head. The bayonet-style wet connectors lock securely and are rated for the pressures encountered in deep technical diving.
Loading into the carry bag
The assembled scrubber and head unit slide into the FX CCR soft bag, which also houses the integrated counterlungs. The blue oxygen hoses are routed through the bag's port openings. The bag acts as the protective shell for the counterlungs and sensitive electronics.
Fitting the HUD module
The heads-up display module is secured into the shoulder strap mount with a Velcro strap. The HUD sits in the diver's field of view during the dive, showing PO2 readouts without needing to look down at the wrist handset.
Assembling the loop
The BOV (Bail-Out Valve) mouthpiece is connected to the corrugated breathing hoses. The inhale and exhale hoses are attached to the correct ports — check the orientation carefully. Unlike a DSV, the BOV has an integrated second-stage regulator: rotating the mouthpiece lever instantly switches the diver to open-circuit bail-out gas directly from the mouthpiece, without reaching for a separate regulator.
Breathing loop close-up
The assembled BOV and breathing loop, showing the oxygen injection fitting (blue collar) and the stainless steel diluent ADV connection. The corrugated hoses connect to the counterlungs inside the bag. The entire breathing loop is now complete.
Securing the scrubber, transmitter and battery pack
With the assembly complete, the scrubber canister, transmitter, and battery pack are secured inside the bag using the Velcro retention straps. The blue oxygen hose is routed cleanly through the bag port. Everything is held firmly in place so nothing shifts during the dive.
First power-up
The Shearwater handset is connected and the unit powered up for the first time. The display shows CC 21/00 (closed-circuit mode, air diluent) with all three O2 cells reading 1.00 — a 1% variance between cells is well within accepted parameters. The FX CCR is assembled, calibrated, and ready for a full pre-dive check.