How to Identify the Correct Life Jacket Re-Arming Kit: CO2 Cylinders, Capsules and Inflator Types

The correct life jacket re-arming kit is identified by the exact jacket model, inflation mechanism, CO2 cylinder specification and manufacturer part number. Cylinder weight on its own is not enough. A 33g cylinder from one system may not have the correct thread, neck, indicator arrangement or approved automatic component for another.

Before ordering, photograph the life jacket label, inflator, cylinder and automatic capsule or hydrostatic unit. Then compare all four identifiers with the manual or manufacturer’s parts list. This guide explains the process and the differences between automatic, manual, Pro Sensor and Hammar systems.

Key facts at a glance

• Start with the jacket’s sewn-in label, product code, manual and inflator markings—not a photograph of the cylinder alone.
• Cylinder gram weight describes the nominal CO2 charge; it does not prove thread, neck length or mechanism compatibility.
• An automatic kit commonly includes a new cylinder and water-sensitive capsule, cartridge or bobbin, but exact contents differ.
• A manual jacket may need a cylinder plus a retaining clip, pin or indicator component after activation.
• A hydrostatic Hammar system uses its own model-specific replacement arrangement and should not be treated as a conventional soluble-capsule inflator.
• Pro Sensor and similar indicator systems must show the correct ready status after re-arming.
• The firing mechanism must be dry and the bladder inspected before new automatic components are fitted.
• Use only manufacturer-approved parts and follow the manual’s fitting and repacking order.
• A life jacket that inflated because of a fault, impact or unexplained water ingress deserves investigation before it is returned to service.
• Keep spare kits dry, labelled by jacket and within their stated replacement dates.

Why compatibility matters

A re-arming kit restores an inflatable life jacket after the cylinder or firing mechanism has been activated. It is part of the tested inflation system, not a generic consumable. The wrong cylinder can underinflate or over-pressurise the bladder. The wrong capsule may fail to fit, activate at an unintended time or leave the status indicator showing a misleading result. A missing retaining clip can allow a manual lever to move.

Search listings often group kits by cylinder size because markings such as 24g, 33g, 38g and 60g are easy to compare. That is useful only after the jacket and inflator have been identified. The same nominal charge can appear in products with different threads and operating heads. Treat the manufacturer kit number as the strongest identifier and cylinder weight as one cross-check among several.

Step 1: identify the life jacket

Open the outer cover only as instructed and photograph every label before removing parts. Record the brand, complete model name, Newton rating, product code, serial number, manufacture date and any service-station notes. “Crewsaver 150N” or “Seago automatic” is not specific enough; a brand can use several mechanisms across current and older models.

If the label is illegible, compare the jacket with the original invoice or contact the manufacturer or retailer using clear photographs of the entire jacket, label area, inflator, cylinder and closure. Do not rely on cover colour because manufacturers often sell the same internal platform in multiple colours and update covers without changing the consumer-facing name.

Life Jacket Outlet groups model-specific options through Crewsaver, Seago and Spinlock re-arming kits, but the model cross-check remains essential.

Step 2: identify the inflation mechanism

The operating head is normally visible once the cover is opened. Read every moulded or printed marking. Common consumer descriptions include UML automatic, UML manual, Pro Sensor, Pro Sensor Elite and Hammar hydrostatic. These labels describe how components fit and how ready/fired status is displayed; they are not interchangeable brand names.

Automatic soluble-element systems react when water reaches and activates the replaceable capsule, cartridge or bobbin. Manual systems require the wearer to pull the toggle. Hydrostatic systems are designed to activate when submerged pressure reaches the system’s threshold and are often chosen to reduce unwanted activation from spray or rain. All automatic jackets also need a manual backup unless the product standard and design state otherwise, but the replacement parts still depend on the exact mechanism.

Step 3: confirm the CO2 cylinder

Read the nominal charge stamped on the cylinder and compare it with the jacket label and manual. Also compare the thread or connection, neck profile and manufacturer kit number. Do not fit a larger charge to gain “extra buoyancy”; the bladder and relief design have been tested as a system.

A cylinder that has fired will normally show a pierced sealing end. Replace it even if it still feels heavy. Deep rust, damaged threads or contamination are also replacement reasons. Some approved servicing processes include weighing the cylinder against its marked gross weight or specification, but that check must use accurate equipment and the maker’s tolerance. It does not make an unapproved cylinder compatible.

Individual CO2 cylinders are useful when the manufacturer specifies that only the cylinder needs changing, but a complete kit is usually clearer after automatic deployment because it includes the associated firing component.

Step 4: confirm the automatic component

Automatic elements can have a printed replacement date, manufacture date or service-life instruction. Read the wording carefully: a date may refer to the component, its packaging or the next service. Use the manufacturer’s interval rather than assuming that all capsules last the same number of years.

A soluble capsule or bobbin exposed to damp conditions can deteriorate even if the jacket has not inflated. A fired component may show a red indicator, missing tablet or changed mechanical position. Replace it with the precise approved item. The store’s re-arming capsules category should be filtered using the inflator and model, not only physical resemblance.

Automatic, manual, Pro Sensor and Hammar systems

Browse automatic kits, manual kits, Pro Sensor kits and Hammar kits only after completing the identification steps.

What normally needs replacing after inflation?

Safe re-arming sequence

The exact order in the manual is mandatory. A general safe workflow is to recover and rinse the jacket as required, open it in a clean dry area, deflate it correctly, remove fired components, inspect the bladder and mechanism, dry everything fully, verify new part numbers and dates, fit the new components in the specified order, confirm all indicators, complete any permitted leak check, and repack using the exact fold sequence.

1. Find the exact manual. Stop if the model or mechanism cannot be positively identified.
2. Determine why it inflated. A genuine immersion, accidental pull and unexplained storage deployment need different investigation.
3. Remove fired parts in the instructed order. Many automatic systems require the water-sensitive element to be removed before the cylinder.
4. Inspect before replacing. Check the bladder, oral tube, webbing, mechanism, cylinder contact area and accessories.
5. Dry completely. Moisture can activate a new soluble component or become trapped against the cylinder.
6. Cross-check every new part. Match model, kit number, cylinder charge, inflator and replacement date.
7. Fit by the approved method. Hand-tighten where instructed; do not use sealants, thread tape or improvised tools.
8. Confirm ready status. Check each indicator and that the pull toggle is accessible.
9. Repack exactly. Position the light, hood and bladder folds so deployment is unobstructed.
10. Record the work. Note date, kit number, component dates and reason for inflation.

Common ordering and fitting mistakes

• Ordering by Newton rating alone: two 150N-class jackets can use different cylinder charges and inflators.
• Ordering by brand alone: a manufacturer may use multiple mechanisms across ranges and production years.
• Replacing only the cylinder after automatic activation: the water-sensitive element may already be spent.
• Reusing an old capsule because it looks intact: status, date and moisture exposure must be checked.
• Installing a new capsule while the head is damp: it may activate during packing or storage.
• Using tools where hand-tightening is specified: threads, seals and operating heads can be damaged.
• Fitting the pull toggle inside the cover: it may be inaccessible in an emergency.
• Copying another model’s fold pattern: a bladder, hood or light can be trapped.
• Testing with the cylinder: this consumes the kit and requires the jacket to be re-armed again.

Which spares should you carry?

Carry at least one complete compatible kit for each different inflation system on board when the voyage and operating rules justify it. The current Workboat Code requires an appropriate re-arming kit for each life jacket on vessels operating in certain offshore categories. Leisure crews also benefit from spares after accidental inflation, particularly on multi-day passages where a replacement cannot be purchased quickly.

Label each sealed kit with the matching jacket model and crew position. Store it dry, protected from crushing and away from fuel, heat and loose metal objects. Review capsule dates during the regular equipment inventory. If the boat carries several jacket types, standardising future purchases can simplify training and spares, but never force an incompatible component into an existing jacket.

When to use an approved service agent

• The model, inflator or kit cannot be positively identified.
• The bladder leaks, seams lift or the oral valve is damaged.
• The mechanism is corroded, cracked or gives conflicting indicator states.
• The jacket inflated without a clear cause.
• The cylinder contact area is abraded or contaminated.
• A harness, structural webbing or buckle is damaged.
• The jacket is used commercially, under a code or under a service contract.
• The manual requires service-station fitting or specialist tools.
• The owner is not confident about folding, routing or accessory compatibility.

Frequently asked questions

Can I use any 33g CO2 cylinder in a 150N life jacket?

No. Gram weight is only one specification. Thread, neck, sealing arrangement, mechanism and manufacturer approval must all match the exact jacket.

Do I need a new capsule if I pulled the manual toggle?

It depends on the mechanism and whether the automatic component fired, expired or was exposed to moisture. Follow the model instructions; do not assume it is reusable.

What is the difference between UML and Hammar re-arming kits?

UML-style systems commonly use a soluble automatic element and separate cylinder. Hammar is a hydrostatic system with its own sealed, model-specific replacement arrangement. The parts and procedures are not interchangeable.

Why does my inflator still show red after I fitted a new cylinder?

The cylinder may not be fully seated, the wrong component may have been fitted, the automatic element may still be fired, or the indicator may require a specific reset sequence. Remove the jacket from use and follow the exact manual.

Can I buy a cylinder and capsule separately?

Yes where the manufacturer specifies those exact parts, but a complete kit reduces the risk of omitting clips, seals or indicators. Confirm part numbers either way.

How long can I keep a spare re-arming kit?

Use the date and storage instructions on the automatic component and packaging. Keep it dry and inspect it during the boat’s safety-equipment review.

Technical references

• Crewsaver — Crewfit 180N Pro user manual and Pro Sensor re-arming instructions
• Baltic — Inflatable lifejacket inspection and re-arming guidance
• Spinlock — Deckvest Hammar re-arming and repacking guidance
• RNLI — Choose It, Wear It lifejacket guide
• MCA — Workboat Code Edition 3