Worth knowing: Hankscraft's own manuals put the same ceramic bypass (part 41206) on the REV 2.5 as on the bigger REV4 — what changed between the valves is the head, not the bypass. So on the back of this smaller head you will find the same thing: one round handwheel on top of the bypass body, clipped on with black clips. Turn the wheel, a ceramic disc does the switching. View: standing behind the unit, looking at the back of the valve. The port sides in this view follow Hankscraft's own manual (RevV2.5 Service Manual, Figure 5-2 — the same bypass section as the RevV4 manual), which labels the inlet on the left and the outlet on the right in this behind-the-unit view. Hankscraft never states the sides in words, so the drawing also marks the field check from §6 of the manual: the meter cable port is always on the OUTLET side.
Right now: SERVICE. The handwheel's pointer sits at SERVICE. If you know the REV4's wheel, you already know this one — same bypass, smaller valve.
Source: Hankscraft Runxin RevV2.5 Service Manual §6 (Ceramic Bypass 41206/41207) — the same bypass section as the RevV4 manual; dealer guides for 7500-REV2.5 systems say "turn knob so the valve is bypassed… turn the bypass SLOWLY to let water in and put in service." CORRECTED 2026-11-02 (accuracy audit): the head is now drawn from the back (the earlier version drew the front display while claiming a behind-the-unit view — the same view mix-up Matthew caught on the Clack file), and the meter port is marked on the outlet side. Honest flags: (1) the exact degrees between stops are not printed in the manual — drawn as about a quarter turn; (2) the inlet/outlet sides rest on the manual's Figure 5-2 drawing alone — Hankscraft never states them in words — so on a real unit the meter cable port is the decider: it is always on the outlet side (manual §6 and start-up steps). VARIANT: some RevV2.5-based systems ship with the 1-inch Push-Pull Bypass 41204 (pushed IN = service, pulled OUT = bypass). Full evidence: animations/accuracy-audit.md.