§4 · component inspection 1 / 5

Component Inspection

Before you assemble, you inspect. The manual treats every component as guilty until proven clean — and so should you. Work through the list slowly. If anything looks suspect, do not dive that part; replace it.

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Head + Electronics

§4 component inspection · head

O-ring surfaces, sensor wells, solenoid port, cable connectors. The head is the brain — treat it that way.

Inspect the H-plate and head body for cracks, dings, and visible damage. §4 · 1: check h-plate unverified
caution Inspect both head-to-bucket O-ring grooves. Clean lint-free; replace if cut or compressed flat. unverified
caution Inspect O2 sensor wells for moisture, corrosion, debris. Dry completely before installing cells. unverified
Inspect the oxygen sensor wiring harness, all three pins seated, no green corrosion. §4 · b: oxygen sensor wiring harness unverified
Inspect the solenoid port and the solenoid valve seat. Clean per manual. unverified
Inspect the head-to-counterlung mating surfaces for nicks or damage. unverified

Oxygen sensors

§4 · component inspection · O2 cells

Record millivolt readings on every dive. Trends are how you catch a failing cell BEFORE it fails on you.

⚠ warning Check cell expiration dates printed on each sensor. None expired, none within 30 days of expiry without a planned replacement. unverified
Cell #1 expiry Cell #2 expiry Cell #3 expiry
Record cell mV in air (PO2 ≈ 0.21). Healthy reading is roughly 8–14 mV at room temperature. unverified

Why this matters

Air reading is the cheap, repeatable baseline. Track this every dive — the dashboard plots the trend so you can spot a sloping cell early.

Cell #1 mV (mV) Cell #2 mV (mV) Cell #3 mV (mV)
⚠ warning Inspect each sensor body for white/yellow crystallization, electrolyte leak, or membrane damage. Reject any cell with visible damage. unverified
Connector pins on each cell are clean, no green oxidation, gold-plated contact intact. unverified

Scrubber basket + bucket

§4 · component inspection · scrubber

A leaking or cracked scrubber kills you fast. Inspect every joint.

Scrubber basket: inspect for cracks, deformed threads, separated foam pads, holes in the nylon mesh. §4 · 12: basket assembly unverified
⚠ warning Bucket body: cracks, gouges, deformation, signs of impact damage. Reject if any structural damage. unverified
Red CO2 seal gasket: gummy but not sticky. Clean if absorbent dust present. Replace if hardened or cracked. §4 · 11: clean red co2 seal unverified
Center tube O-ring: undamaged, seated cleanly. unverified

Counterlungs + hoses

§4 · component inspection · counterlungs

Pinhole leaks here let water into your loop. Find them now, not at depth.

Inhalation counterlung: no pinholes, no fabric delamination, all stitching intact. unverified
Exhalation counterlung: same checks. OPV nozzle and mounting threads undamaged. unverified
Manual O2 add valve (MAV) on exhale lung: clean, smooth action, button returns under spring. unverified
Counterlung quick-connects on both sides: O-rings clean and greased; ferrules undamaged. unverified
Breathing hoses (inhale + exhale): inspect end-to-end for cracks, kinks, T-piece damage, hose-clamp tightness. §4 · 13: disassemble mouthpiece to counterlung hose unverified
⚠ warning Mushroom valves at both T-pieces: present, seated cleanly, free of debris, no curling or hardening. unverified

Why this matters

A folded mushroom valve = unidirectional flow lost = CO2 in your inhale loop.
⚠ warning BMCL only: confirm the inner counterlung bladder is the 420D nylon version and the inner retaining ring is the 26260 stainless-steel part. The earlier polyurethane bladder and 26203 plastic snap ring are recalled for failures during normal use. Hollis service bulletins HR.0003 / HR.0004 unverified

Why this matters

Hollis service bulletins HR.0003 / HR.0004 — recalled inner bladder and snap ring can fail mid-dive and compromise the loop. FMCL configurations are unaffected.

DSV / BOV + mouthpiece

§4 · component inspection · DSV

DSV/BOV lever moves crisply between open and closed. No mush, no detent skipping. §4 · 3: inspect dsv breathing unverified
Mouthpiece bite tabs intact, not chewed through. Replace if cracked. unverified
If BOV: bailout regulator demand valve seal intact, no free-flow when pressurized. unverified
BOV regulator first stage HP/IP within spec from last service. unverified

Electronics + batteries

§4 · component inspection · batteries

Record battery voltages every dive. The dashboard charts drift so you replace before low-voltage shutdown surprises you.

caution Primary electronics battery: voltage above replacement threshold per manual. Record reading. unverified
Primary battery (V)
Solenoid battery (if separate): voltage above threshold. Record reading. unverified
Solenoid battery (V)
HUD / wrist computer battery state: green or above-threshold. Record reading. unverified
HUD battery (V)
Battery compartment O-rings inspected, clean, greased; cover threads engage smoothly. §4 · battery compartment cover unverified
Solenoid bench-test (if available): audible click when energized, no stuck plunger. unverified

Onboard gas cylinders + regulators

§4 · component inspection · gas

O2 cylinder: in service, not overdue for hydro or visual; valve clean; no debris. unverified
Diluent cylinder: same checks. unverified
O2 regulator first stage IP within spec. unverified
Diluent regulator first stage IP within spec. unverified
⚠ warning O2 cleanliness on the O2 side of the system: all components O2 service. unverified