Choose a master equipment identity
Use the complete-set serial and a stable internal unit reference. When the serial is unreadable, maintain an explicitly provisional identity supported by photographs and site records. Do not use manufacturer and kW alone as a unique key; several physical machines may share those values.
Map the alternate references
List earlier asset tags, warehouse numbers and listing references beside the master record. Check evidence before merging entries. Similar photos or matching models are not enough to conclude that two listings concern the same unit. Keep uncertain matches separate for review.
Link bids to their actual source event
Record the buyer, date, package version and proposal reference. Mark a forwarded copy as a copy, and link revised proposals to their originals. Do not count the same proposal twice because it arrived through two channels or was entered by two staff members.
Maintain one availability decision
Assign a coordinator for changes such as withdrawal, partial sale or completed collection. Update the authorized channels using the current master facts. Preserve history while clearly marking which record is current, so an obsolete listing does not continue to imply that sold or retained equipment is available.