Replacing a cylinder without changing tenant keys

Why a single failure can become a site-wide event

A cylinder is a mechanical assembly, and mechanisms fail. The problem is not the failure — it is that replacing one cylinder with an off-the-shelf part invalidates the keying structure for every unit it was grouped with.

What makes a like-for-like replacement possible

Three records decide it:

1. Model and cylinder size — so the physical part matches.
2. The keying schedule — so the new cylinder is pinned to the same key as the one it replaces. See how the three keying structures differ if it was never written down.
3. The supplier reference number — so the records can be retrieved years later.

With those three, a single cylinder can be produced to match without touching any other unit.

Where to keep the record

Keep it in two places: your own facility file, and with the supplier against your account. If it exists only in one former employee's email, it does not exist.

When a full rekey really is unavoidable

A rekey is the honest answer when:

• The keying schedule was never recorded
• The original cylinder model is discontinued and no equivalent keyway is available
• A site master key has been lost, not a single tenant key
• The group was keyed alike and a group key has gone missing

In those cases, plan it as a project: notice to tenants, a fitting schedule, and new keys issued unit by unit.

Preventing the next one

Order a small stock of spare cylinders at the site's exact specification with the original order. They cost little at that point and remove the temptation to substitute a local part later.