A peritoneal dialysis system (10a, 10b, 10c, 10d) comprising: a cycler including a pump actuator, a heater and a heating pan operable with the heater, wherein the heating pan includes a sidewall forming a slot; and a disposable set operable with the cycler, the disposable set including a pumping cassette including a pump chamber configured to be actuated by the pump actuator, and a heater/mixing container in fluid communication with the pumping cassette and sized to be received at the heating pan, the heater/mixing container including a port configured such that when the port is slid into the slot of the heater pan sidewall, the port is prevented from rotating about an axis transverse to a direction of flow through the port, wherein the port includes a member that abuts first and second sides (94, 94a) of the slot when the port is slid into the slot to prevent the port from rotating about an axis inline with the direction of flow through the port, characterized in that the slot includes an angled or V-shaped section through which a portion of the port is inserted and a circular section for receiving the portion of the port, and in that a transition from the angled or V-shaped section to the circular section is sized so that the portion of the port press-fits through the transition to provide tactile feedback. a cycler including a pump actuator, a heater and a heating pan operable with the heater, wherein the heating pan includes a sidewall forming a slot; and a disposable set operable with the cycler, the disposable set including a pumping cassette including a pump chamber configured to be actuated by the pump actuator, and a heater/mixing container in fluid communication with the pumping cassette and sized to be received at the heating pan, the heater/mixing container including a port configured such that when the port is slid into the slot of the heater pan sidewall, the port is prevented from rotating about an axis transverse to a direction of flow through the port, wherein the port includes a member that abuts first and second sides (94, 94a) of the slot when the port is slid into the slot to prevent the port from rotating about an axis inline with the direction of flow through the port, characterized in that the slot includes an angled or V-shaped section through which a portion of the port is inserted and a circular section for receiving the portion of the port, and in that a transition from the angled or V-shaped section to the circular section is sized so that the portion of the port press-fits through the transition to provide tactile feedback. a pumping cassette including a pump chamber configured to be actuated by the pump actuator, and a heater/mixing container in fluid communication with the pumping cassette and sized to be received at the heating pan, the heater/mixing container including a port configured such that when the port is slid into the slot of the heater pan sidewall, the port is prevented from rotating about an axis transverse to a direction of flow through the port, wherein the port includes a member that abuts first and second sides (94, 94a) of the slot when the port is slid into the slot to prevent the port from rotating about an axis inline with the direction of flow through the port, characterized in that the slot includes an angled or V-shaped section through which a portion of the port is inserted and a circular section for receiving the portion of the port, and in that a transition from the angled or V-shaped section to the circular section is sized so that the portion of the port press-fits through the transition to provide tactile feedback.