Remove the cap nuts of the connecting pipes (2) (324) and connecting tube (2) with the hook spanner (818). Loosen the union nuts (326) at the bottom of the connection pipes and tube with the hook spanner (818) and direct them sideways to make sure that when the cover is removed, they do not get in the way. (Fig. 2-1) Use care to prevent loss of the flow rate regulating orifice inserted in the portion indicated by the arrow. (Fig. 2-2) Remove the cover nut (317) with a spanner. (Fig. 2-2)