Abstract: A volume compensator assembly for a vapor canister includes a partition adapted to be disposed in an interior chamber of the vapor canister and having a single opening extending therethrough. The volume compensator assembly also includes a grid pattern disposed on the partition about the opening to guide airflow to the opening. The volume compensator assembly further includes a spring connected to the partition and contacting the vapor canister to move the partition for compensation of a volume of a bed of vapor adsorbing material in the vapor canister.