A treatment system comprising: an infusion line (13; 42; 365); an infusion apparatus (12; 36; 362) controllable to provide a fluid flow from a replaceable fluid dispenser at a set flow rate downstream therefrom, wherein the fluid flow comprises a plurality of boluses, and further wherein the infusion apparatus (12; 36; 362) comprises an actuator configured to operate on the replaceable fluid dispenser to provide one bolus of the plurality of boluses into the infusion line (13; 42; 365) when commanded; and a controller, characterized in that the controller is configured to: determine, upon connection of a replacement fluid dispenser in the infusion apparatus (12; 36; 362), if the infusion apparatus (12; 36; 362) is being prevented when commanded from delivering one or more boluses downstream of the infusion apparatus (12; 36; 362), and prime the pressure in the replacement fluid dispenser if it is determined that the infusion apparatus (12; 36; 362) is being prevented from delivering one or more boluses downstream of the infusion apparatus (12; 36; 362), wherein the controller is configured to prime the pressure in the replacement fluid dispenser by accelerating one or more commands to the infusion apparatus (12; 36; 362) to deliver one or more boluses into the infusion line (13; 42; 365) so that pressure in the replacement fluid dispenser increases and a time required to deliver boluses is decreased, wherein a time interval between an accelerated command and a prior command immediately preceding the accelerated command is less than a time interval between commands provided to deliver boluses at the set flow rate. an infusion line (13; 42; 365); an infusion apparatus (12; 36; 362) controllable to provide a fluid flow from a replaceable fluid dispenser at a set flow rate downstream therefrom, wherein the fluid flow comprises a plurality of boluses, and further wherein the infusion apparatus (12; 36; 362) comprises an actuator configured to operate on the replaceable fluid dispenser to provide one bolus of the plurality of boluses into the infusion line (13; 42; 365) when commanded; and a controller, characterized in that the controller is configured to: determine, upon connection of a replacement fluid dispenser in the infusion apparatus (12; 36; 362), if the infusion apparatus (12; 36; 362) is being prevented when commanded from delivering one or more boluses downstream of the infusion apparatus (12; 36; 362), and prime the pressure in the replacement fluid dispenser if it is determined that the infusion apparatus (12; 36; 362) is being prevented from delivering one or more boluses downstream of the infusion apparatus (12; 36; 362), wherein the controller is configured to prime the pressure in the replacement fluid dispenser by accelerating one or more commands to the infusion apparatus (12; 36; 362) to deliver one or more boluses into the infusion line (13; 42; 365) so that pressure in the replacement fluid dispenser increases and a time required to deliver boluses is decreased, wherein a time interval between an accelerated command and a prior command immediately preceding the accelerated command is less than a time interval between commands provided to deliver boluses at the set flow rate. determine, upon connection of a replacement fluid dispenser in the infusion apparatus (12; 36; 362), if the infusion apparatus (12; 36; 362) is being prevented when commanded from delivering one or more boluses downstream of the infusion apparatus (12; 36; 362), and prime the pressure in the replacement fluid dispenser if it is determined that the infusion apparatus (12; 36; 362) is being prevented from delivering one or more boluses downstream of the infusion apparatus (12; 36; 362), wherein the controller is configured to prime the pressure in the replacement fluid dispenser by accelerating one or more commands to the infusion apparatus (12; 36; 362) to deliver one or more boluses into the infusion line (13; 42; 365) so that pressure in the replacement fluid dispenser increases and a time required to deliver boluses is decreased, wherein a time interval between an accelerated command and a prior command immediately preceding the accelerated command is less than a time interval between commands provided to deliver boluses at the set flow rate.