The scrubber canister can be packed with approximately 5 pounds of loose granular CO2 absorbent.
Dive Rite recommends Intersorb 812 or Sofnolime 797 (8-12 mesh) granular absorbent. 408 (4-8 mesh) is not recommended. It is important to use fresh absorbent for every dive. Granular absorbent should never be reused.
To pack the scrubber, begin by inspecting all of the scrubber components. Look for any damage, dirt, debris, or excess lubrication on the scrubber canister, scrubber end cap, electronics head, bore plug nut, and seals and O-rings. Any damage or contamination can cause a loss of water integrity and flooding of the breathing loop.
Dive Rite includes a filter disc that should be used when packing the scrubber with granular absorbent.
This is to reduce the amount of dust that reaches the head and the rest of the breathing loop. It is placed in the bottom of the scrubber body, underneath the stainless steel mesh screen. This filter is optional when using an ExtendAir cartridge. The filters are reusable but will need to be replaced eventually. Replacements can be ordered from Dive Rite in packs of 3.
Ensure that the filter is in place and the stainless steel screen mesh is correctly seated on top of it in the bottom of the scrubber canister (See Figure 4).
Begin pouring granular absorbent into the canister (See Figure 5).
Fill the canister approximately half full and then tap around the outside of the canister to settle and level the absorbent (See Figure 6).
Continue filling with absorbent until it is approximately ¼ inch (6mm) from the top of the canister. Again tap around the outside of the canister to continue settling and compacting the absorbent. If necessary, add more absorbent to bring the fill level back to ¼” (6mm) from the top of the canister.
Place the top plate with attached screen on top of the canister with the screen side down. It should be flush with the inside edge of the canister (See Figure 7). If it is not, add or remove absorbent and relevel until it is. Note -the wire handle on the top plate is only for removing the plate. It is not a carry handle for the scrubber.
Next, place the wave spring around the stainless steel center tube, on top of the top plate. Finally, orient the nut with the tapered side up and thread it onto the center tube (*Note that the nut is installed in one direction when using an EAC and the other direction for a packed scrubber). Make sure that the spring sits in the small counterbore in the nut. This keeps the spring centered on the top plate (See Figure 8). Hand tighten the nut to compress the wave spring against the top plate. Do not overtighten the nut.
The nut and spring are not intended to apply pressure to “pack” the scrubber. They are only to ensure an even pressure is held on the top plate after properly packing it.
The canister is packed correctly if shaking the canister does not result in noise being heard from the absorbent. Any movement of the absorbent can lead to channeling and premature CO2 breakthrough. If needed, remove the lid and continue tapping the sides of the canister and adding more material as necessary.
Clean up any excess absorbent dust before installing the scrubber canister. The dust will quickly react with any exposure to water and can create a caustic solution in the breathing loop.