When the original valve is obsolete, first reconstruct its function and installation requirements. A candidate should be compared against evidence, not selected from appearance alone.
Send the original reference: Include the complete model code, quantity, destination and available photos or drawings.
Build the original reference record
- Complete model and order numbers
- Readable nameplate and all-side photos
- Hydraulic symbol or machine schematic
- Mounting face, port and envelope dimensions
- Voltage, connector and manual override
Separate must-match and adaptable fields
| Field | Normally must match | May be adaptable with engineering review |
|---|---|---|
| Hydraulic function | Spool symbol, center condition and controlled ports | Pilot arrangement only if the circuit is redesigned |
| Installation | Mounting interface and safe pressure rating | Envelope, connector direction or plumbing |
| Electrical | Supply type and voltage | Connector style with approved rewiring |
| Performance | Required pressure, flow and fluid compatibility | Response or leakage only when the application permits |
Document the decision
- Original reference and proposed model
- Data sources used
- Known differences
- Required customer changes
- Sample, commissioning and approval plan
Where obsolete references commonly turn up
Recognizing the source of an obsolete reference helps route it to the right evidence. The same series name can arrive through very different channels.
| Situation | Typical evidence available | Main risk |
|---|---|---|
| Machine still in service with a failed valve | Nameplate, machine model, schematic and operating history | A visually similar valve with a different function or size |
| Storeroom or second-hand stock | Part label, box marking and limited installation history | A stored unit whose revision or suffix differs from the drawing |
| Catalog or BOM entry from an old machine manual | Old catalog page, order code and machine BOM | Multiple catalog generations sharing one series label |
Evidence to keep with the final record
- Photograph or scan of the original nameplate
- Machine make, model, serial number and circuit reference
- The complete code from the catalog generation that matches the machine
- Any dimension, drawing or test note used to compare the candidate
- The approved differences and the person responsible for approval