Removal device for removing gas bubbles and/or dirt particles from a liquid in a liquid conduit system or for removing particles of a heavier or lighter liquid from the liquid in the liquid conduit system, the removal device comprising: - an entry , - at least one exit , - a housing which defines an inner space , - a main flow channel extending from the entry to the exit at least in part through the inner space, the main flow channel being defined by one tube or by a first and second tube , - at least one branch flow passage formed by a series of holes in the single tube or formed between an end of the first tube 220A and an end of the second tube , the branch flow passage allowing fluid communication between the main flow channel and a quiet zone outside the tube and within the inner space which is defined by the housing , - at least one return flow passage the return flow passage allowing a return flow from the quiet zone outside the tube back into the main flow channel , wherein the return flow passage is located in the housing at an upstream side of the housing and upstream of a plate , when viewed along the direction of flow in the main channel, wherein the return flow passage is formed by a transverse tube extending from an area which is surrounded by a housing wall , the plate and by the single tube or by the first tube , the transverse tube extending into the main flow channel , wherein - when viewed in the direction of the main channel - the transverse tube extends transverse to the main flow channel and - when viewed in side view - the transverse tube extends in a downstream direction of the main flow channel, and wherein the quiet zone has a greater cross-sectional area than the main channel and wherein the removal device is constructed to branch off only a relatively small portion of the main flow, with the result that in use the liquid in the at least one quiet zone has a smaller velocity than the liquid in the main flow channel , allowing dirt or particles of a heavier liquid to settle and/or allowing gas bubbles or particles of a lighter liquid to rise in the quiet zone. - an entry , - at least one exit , - a housing which defines an inner space , - a main flow channel extending from the entry to the exit at least in part through the inner space, the main flow channel being defined by one tube or by a first and second tube , - at least one branch flow passage formed by a series of holes in the single tube or formed between an end of the first tube 220A and an end of the second tube , the branch flow passage allowing fluid communication between the main flow channel and a quiet zone outside the tube and within the inner space which is defined by the housing , - at least one return flow passage the return flow passage allowing a return flow from the quiet zone outside the tube back into the main flow channel , wherein the return flow passage is located in the housing at an upstream side of the housing and upstream of a plate , when viewed along the direction of flow in the main channel, wherein the return flow passage is formed by a transverse tube extending from an area which is surrounded by a housing wall , the plate and by the single tube or by the first tube , the transverse tube extending into the main flow channel , wherein - when viewed in the direction of the main channel - the transverse tube extends transverse to the main flow channel and - when viewed in side view - the transverse tube extends in a downstream direction of the main flow channel, and <EOS>