Owning a closed-circuit rebreather is fundamentally different from owning open-circuit scuba equipment. An OC regulator needs an annual service and an occasional visual inspection of your cylinder. A CCR is a life support system with multiple components that require regular attention, and the quality of that maintenance directly affects your safety underwater.
The good news is that CCR maintenance is not complicated once you understand the rhythm. It breaks into three categories: what you do before and after every dive, what you do periodically between dives, and what gets done by a certified service technician at scheduled intervals. Here is a practical guide to each.
Pre-Dive: The Checks That Keep You Alive
Every CCR dive starts with a thorough pre-dive checklist, and there are no shortcuts. On the AP Diving Inspiration, the pre-dive routine takes about 15 to 25 minutes once you are practiced. Rushing it is never acceptable.
Scrubber Packing
The scrubber canister is packed with Sofnolime, a granular material that chemically absorbs carbon dioxide from your exhaled breath. Proper packing technique matters. The Sofnolime must be evenly distributed and adequately compressed so there are no channels for gas to bypass the absorbent material. Uneven packing can allow CO2-laden gas to pass through the scrubber without being fully processed, which is dangerous. Follow the canister packing procedure in the AP Diving manual precisely, and use the correct grade and quantity of Sofnolime for your canister size.
Oxygen Cell Verification
The AP Diving Inspiration uses three oxygen cells to measure the partial pressure of oxygen in the breathing loop. Before each dive, verify that all three cells are reading accurately and within acceptable tolerance of each other. The 2020 Vision display shows the ppO2 reading from each cell individually. If any cell is reading significantly differently from the other two, or if any cell has exceeded its recommended service life, replace it before diving. Oxygen cells are consumable components with a finite lifespan. They degrade gradually, and a cell that was accurate last week is not guaranteed to be accurate today.
Positive and Negative Pressure Tests
These tests confirm the integrity of your breathing loop. A positive pressure test checks that the loop holds pressure without leaking gas outward. A negative pressure test confirms it does not allow water to leak inward. Both tests take only a couple of minutes but are essential. A loop that leaks is a loop that can flood, and a flooded loop is one of the failure scenarios your training prepared you for but that proper maintenance should prevent.
Electronics Check
Power on the dual controllers and the 2020 Vision display. Verify battery levels (the intelligent dual battery system shows B1 and B2 status). Confirm that both C1 and C2 controllers are active and that the fiber optic HUD shows two green lights. Set your ppO2 setpoint for the planned dive. This electronic check takes moments but confirms that the life support systems are functional before you enter the water.
Post-Dive: The Routine That Protects Your Investment
What you do in the 30 minutes after a dive has a significant impact on your unit’s long-term reliability.
Rinse and Dry
Freshwater rinse the exterior of the unit as soon as practical after every dive, particularly if diving in salt water. Salt crystal buildup on connectors, hose fittings, and the counterlung fabric accelerates corrosion and material degradation. Disassemble the breathing loop components, rinse them individually, and allow them to dry thoroughly. Moisture trapped inside the loop promotes bacterial growth and can affect sensor accuracy over time.
Scrubber Management
If you are diving again the next day and the scrubber still has remaining capacity (monitored via the Temp-Stick during the dive), you may be able to reuse the canister. However, once Sofnolime has been exposed to moisture, its efficiency begins to decline even when not in use. If there will be a gap of more than a day or two between dives, it is better practice to empty the canister, discard the used Sofnolime, and pack fresh material before your next dive. When in doubt, pack fresh.
Mouthpiece and DSV
The dive/surface valve (DSV) and mouthpiece see significant mechanical use and exposure to moisture. Rinse thoroughly and inspect the mushroom valves for any signs of wear, tearing, or deformation. These small one-way valves direct the gas flow through the correct path in the loop and a failed mushroom valve can allow exhaled CO2-laden gas to mix with your fresh gas supply.
Periodic Maintenance: Between Dive Days
Oxygen Cell Replacement
Oxygen cells have a finite lifespan, typically measured in months of exposure to oxygen. The exact replacement interval depends on usage patterns and storage conditions, but as a general rule, cells should be replaced according to the manufacturer’s recommended schedule. AP Diving’s co-axial connectors with gold-plated push-on, pull-off connections make cell replacement straightforward. Always verify new cells against a known gas source after installation.
O-Ring Inspection
The breathing loop relies on multiple O-rings to maintain its seal. Periodically inspect all accessible O-rings for nicks, flat spots, or degradation. Replace any O-ring that shows wear. The cost of an O-ring is negligible. The cost of a flooded loop during a dive is not.
Hose and Counterlung Inspection
Examine hoses for kinks, cracks, or areas of wear, particularly where they bend or contact other equipment. Inspect counterlungs (whether OTS or BMCL) for fabric integrity, check the manual inflator mechanisms, and verify the overpressure relief valve functions correctly.
Annual Service: The Professional Check
At least once per year, or at the interval specified in your unit’s service schedule, the Inspiration should be inspected by a certified AP Diving service technician. This full service covers areas that are beyond routine owner maintenance:
- First stage regulators on both O2 and diluent cylinders
- Solenoid function and calibration
- Controller electronics and firmware
- ADV (Auto Diluent Valve) inspection and service
- Chassis and canister integrity
- Full system leak test under controlled conditions
- Battery pack assessment
AP Diving’s modular design philosophy makes servicing more accessible than many other CCR platforms. Components are designed to be inspected, serviced, and replaced individually without dismantling the entire unit. This is a direct benefit of the in-house manufacturing approach, where every component is designed with service access in mind.
Why Maintenance Matters More on CCR
On open circuit, a poorly maintained regulator might freeflow or breathe harder than it should, but you can usually manage the situation and end the dive safely. On a rebreather, the consequences of deferred maintenance are more serious because the system is actively managing your breathing gas composition. A failing oxygen cell, a channeled scrubber, or a leaking loop can create conditions that are subtle at first and dangerous if undetected.
This is not meant to be alarming. Properly maintained, the AP Diving Inspiration is an exceptionally reliable system with multiple layers of redundancy. The dual oxygen controllers, the Temp-Stick scrubber monitoring, and the fiber optic HUD all exist to catch problems before they become emergencies. But those safety systems complement good maintenance. They do not replace it.
Silent Diving provides full service support for the AP Diving Inspiration range across the Americas. Whether you need routine annual maintenance, a cell replacement, or a full overhaul, our factory-trained technicians have the expertise and parts inventory to keep your unit in peak condition.
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