A pump assembly for serial connection along a primary fluid line , the pump assembly comprising: a pump having an inlet side and an outlet side , and configured to receive a first fluid from the inlet side , and expel the first fluid from the outlet side ; and a pump bypass actuatable between first and second valve states: the first valve state fluidly connecting the pump in series along the primary fluid line , and connecting an input side of the primary fluid line to an output side of the primary fluid line only via the pump ; and a second valve state fluidly isolating the pump from the primary fluid line , and fluidly connecting the input and output sides of the primary fluid line via a continuously piggable path , wherein the pump bypass further comprises: a piggable passage extending from the input side of the primary fluid line to the output side of the primary fluid line , and interrupted only by a bypass valve ; a pump inlet valve disposed fluidly between the piggable passage and the inlet side of the pump ; and a pump outlet valve disposed fluidly between the piggable passage and the outlet side of the pump ; and wherein the piggable passage shares a passage width and a passage shape with the primary fluid line , such that a pig (P) can run snugly through the input side of the primary fluid line , the piggable passage , and the output side of the primary fluid line , without interruption, while the bypass valve is open. a pump having an inlet side and an outlet side , and configured to receive a first fluid from the inlet side , and expel the first fluid from the outlet side ; and a pump bypass actuatable between first and second valve states: the first valve state fluidly connecting the pump in series along the primary fluid line , and connecting an input side of the primary fluid line to an output side of the primary fluid line only via the pump ; and a second valve state fluidly isolating the pump from the primary fluid line , and fluidly connecting the input and output sides of the primary fluid line via a continuously piggable path , the first valve state fluidly connecting the pump in series along the primary fluid line , and connecting an input side of the primary fluid line to an output side of the primary fluid line only via the pump ; and a second valve state fluidly isolating the pump from the primary fluid line , and fluidly connecting the input and output sides of the primary fluid line via a continuously piggable path , wherein the pump bypass further comprises: a piggable passage extending from the input side of the primary fluid line to the output side of the primary fluid line , and interrupted only by a bypass valve ; a pump inlet valve disposed fluidly between the piggable passage and the inlet side of the pump ; and a pump outlet valve disposed fluidly between the piggable passage and the outlet side of the pump ; and wherein the piggable passage shares a passage width and a passage shape with the primary fluid line , such that a pig (P) can run snugly through the input side of the primary fluid line , the piggable passage , and the output side of the primary fluid line , without interruption, while the bypass valve is open. a piggable passage extending from the input side of the primary fluid line to the output side of the primary fluid line , and interrupted only by a bypass valve ; a pump inlet valve disposed fluidly between the piggable passage and the inlet side of the pump ; and a pump outlet valve disposed fluidly between the piggable passage and the outlet side of the pump ; and wherein the piggable passage shares a passage width and a passage shape with the primary fluid line , such that a pig (P) can run snugly through the input side of the primary fluid line , the piggable passage , and the output side of the primary fluid line , without interruption, while the bypass valve is open. <EOS>