The bypass is not in your plumbing. It is a compact block bolted to the back of the control head, about as wide as the head itself, with two small red arrow handles on it. (The handles are drawn in magenta so they stay visible — on your unit they are red plastic.) This drawing faces the FRONT of the unit — the display side, the way Clack's own manual draws the bypass (Bypass Valve section, Figures 1–4). Facing the front: water enters on the RIGHT and exits on the left — that is the Clack installation manual's own sentence. Stand behind the real unit to work the handles and left and right swap: from behind, the inlet is on YOUR left.
Right now: SERVICE. The arrows point the way the water flows — the inlet arrow (right side, facing the front) aims down into the valve, the outlet arrow (left side) aims up and out to the house pipe. That is exactly how the Clack manual words it: the handles show the direction of flow.
Sources: Clack WS1 & WS1.25 Service Manual, Bypass Valve section, Figures 1–4 (assembly V3006): two plug valves turned by red arrow-shaped handles; in Normal Operation the handles point in the direction of flow; in Bypass both arrow tips point to the center. Port sides: Clack WS1 Installation & Starting Manual — “As you face the Clack WS1 control from the front, the water enters on the right and exits on the left”; Dime Water Inc.'s Clack instructions say the same (“flow from right — untreated inlet — to left — treated outlet — when viewed facing the valve timer”). CORRECTED 2026-11-02 (accuracy audit): the earlier version of this file claimed a behind-the-unit view while drawing the front display on the head — read as the front, its inlet and outlet were on opposite sides from the real valve, which is what Matthew caught. It is now drawn in the front view, matching Clack's own figures. This valve also has diagnostic and shut-off positions — the two above are the homeowner positions. Full evidence: animations/accuracy-audit.md.