The original RD1 unit can be extended beyond oxygen-only (very shallow) depths with the introduction of a diluent manual addition valve run off of the onboard air cylinder. The MAV injections are disbursed across the sensor faces to wick moisture and validate sensor function. When coupled with a pO2 display and proper training, this configuration allows depth extensions to 2ATA.
WARNING: Do not operate RD1 or any rebreather with a diluent gas without a pO2 monitoring device. Consult your instructor for guidance.
