When determining if a vent connector of a smaller size may be used on an appliance that has a larger flue collar the reduction in size of the connector of no more than one table size is appropriate if the vent connector is no larger t han ____ inches.

When determining if a vent connector of a smaller size may be used on an appliance that has a larger flue collar the reduction in size of the connector of no more than one table size is appropriate if the vent connector is no larger t han ____ inches.