Abstract: A power oil or gas burner having a centrifugal blower that includes a standardized production scroll housing. Within the space available in the scroll housing a narrow-width, large (maximum) diameter squirrel cage rotor is provided, that is offset away from the air inlet ring of the blower. In combination with a scroll extension carried by the housing and disposed adjacent the rotor, the invention provides a unique barrier wall member that is mounted in the housing and extends within the squirrel cage rotor, such barrier member providing for a more stable flow of air at higher static pressures and higher capacity that was previously attainable, and reducing whine and whistle from the blower operation.