method to be used because the entire system gravity drains into the inlet manifold it is only necessary to flush that manifold a small flush tank 9 of flushing liquid 23 is located above the inlet manifold 4 and connected to it by a tube 11 and valve 10 once the system is drained valve 10 is opened for a short period flushing the manifold 4 into the last used tank the addition of a small quantity of clear fluid should have no effect upon the dye in the tank and might serve to make up for losses from the fount due to evaporation and paper absorption it this is not desired a drain valve 31 can be installed in the side of the inlet manifold 4 level as in valves 7 and a tube 32 led from that valve 31 to a catch basin or pail 33 the contents of which may be discarded after flushing or recycled back to tank 9 if desired the flush tank may be connected with the outlet manifold as shown at 34 flushing both manifolds fig5 shows a timing diagram to clarify the sequence of operations of the invention in use at the beginning to the tinter is running color 1 i e blue from tank 34 a 34 inlet 7a and outlet 6a valves to that tank are open the operator wishes to switch the system to color 2 i e green from tank 34 b 34 at t1 he begins the change over at t1 he begins the change over valve 6a is closed admitting no further fluid from tank 34 a 34 and the pump 22a is turned off the valves 6 and pumps.