Why should a rebreather diver always pre-breathe the rebreather before diving?
Pre-breathing the rebreather warms up the absorbent material towards its optimum working temperature before the dive begins. Pre-breathing also allows the diver to confirm that the rebreather is functioning correctly whilst you are safely out of the water. Very importantly, pre-breathing is your only check for CO2 contamination before you dive. If you get a CO2 hit whilst pre-breathing on the boat or land you will survive. Underwater might result in a different outcome!
