The easiest wrong purchase is a part that looks almost identical. Equipment manufacturers can change a connection, a moulding or a seal profile between model revisions.
Start with the rating plate
Look for an accessible label carrying the model and serial number. It may be near an opening, inside the cabinet or on the base. Record the entire code, including letters, slashes and suffixes. Do not remove covers or move heavy equipment unsafely just to reach a label.
Keep equipment and part numbers separate
The machine model tells us which equipment you own. A number printed on the old component identifies the part. Both are useful, but they are not interchangeable.
Record the differences
For a seal, note the door position and profile. For hardware, note hinge side and mounting-hole spacing. For a filter, compare the manufacturer’s compatibility list. Dimensions alone do not prove fit.
Ask before ordering
Send the model, serial number, existing part code and delivery postcode through the part finder. Keep photos ready in case we need to check a label or connection.