The Yale YS170-3H35 / YS170-3H45 is a lever-operated YS170 multipoint lock with a central latch and hookbolt plus two remote reverse-action hookbolts. The retained versions have 35mm and 45mm backset options, 92mm PZ centres and a 16mm faceplate.
Lift the handle to engage the hook locking points, then turn the cylinder key to deadlock the mechanism. Unlock with the key before lowering the handle to release the locking points and latch. Closing on the latch or lifting the handle alone is not the fully key-locked state.
The latch hold-back snib, where fitted, retains the withdrawn latch for free passage. Yale specifies withdrawing and holding the latch, sliding the faceplate snib upwards to retain it, and sliding it downwards to release it. This is latch retention, not an extra latch-deadlocking security function.
With the matching nightlatch furniture and spindle arrangement, the outside handle releases the hooks but does not withdraw the latch; the key is then used to retract the latch. Standard lever/lever operation is different. Check the existing furniture and required outside operation rather than assuming an offset lever/pad will fit every split-spindle case.
Replacement fit: compare the exact reference and generation, backset, PZ centres, follower arrangement, faceplate shape, case routing, fixing holes, locking-point positions and profile-specific frame keeps. A matching brand or 92mm PZ measurement alone does not establish a direct replacement.
Yale describes tested YS170 doorset configurations and approved hardware combinations. PAS 24 security and BS 6375 performance evidence applies to the relevant complete tested doorset, not automatically to every replacement lock installation. Check the exact doorset specification; BS 6375 is not another security certification.
