Every year, plants close, production lines get upgraded, and equipment gets decommissioned. The automation components from these facilities don't disappear—they enter the surplus market. This creates an opportunity to buy quality parts at 30-70% below OEM pricing.
But the surplus market also has pitfalls. Counterfeit parts, failed units sold "as-is," and misrepresented conditions are real risks. Here's how to navigate the market and get reliable parts.
Understanding Part Conditions
Surplus automation parts generally fall into a few categories. Make sure you know what you're actually buying:
New Old Stock (NOS)
Genuine OEM parts never installed. May be from cancelled projects, overstock, or decommissioned systems. Should be in original packaging with intact labels.
Tested & Reconditioned
Previously in service, removed, tested, and repaired to working condition. Quality varies—ask what was tested and what was replaced.
Pulled / Used
Removed from operating equipment with minimal testing. Appropriate for non-critical applications or when you can test before installation.
Repair / Exchange
Sold without functional guarantee. Good for core exchange programs or when you have repair capability in-house.
Red Flags When Buying Surplus Parts
- Prices too good to be true. If someone's selling a ControlLogix CPU for 80% off, ask yourself why. Legitimate surplus pricing reflects testing, handling, and warranty costs.
- "As-is, no returns" on critical parts. Reputable surplus dealers stand behind their products. No warranty usually means no confidence in the product.
- Stock photos only. For surplus parts, you should be able to request actual photos of the unit you're buying, showing labels, condition, and any wear.
- No physical address or phone number. Legitimate industrial surplus dealers have facilities for receiving, testing, and storing inventory. Web-form-only contact is suspicious.
- Suspiciously new-looking labels on "used" parts. Counterfeit parts exist in the automation market, particularly for popular Allen-Bradley and Siemens modules.
Questions to Ask Before Buying
Essential Questions for Your Supplier
What's the warranty? 90 days is a minimum; 12 months is standard for reputable surplus dealers.
How was the part tested? "Bench tested" means it powered on. "Functionally tested" should mean actual I/O or communication verification.
What's the return policy? Can you return the part if it doesn't work in your application (not just DOA)?
What's the part's history? Where did it come from? A cleanroom semiconductor fab vs. a foundry makes a difference.
Is the firmware current enough? For CPUs and communication modules, firmware version matters for system compatibility.
Checking Parts When They Arrive
- Inspect physically. Look for corrosion, burn marks, damaged pins, loose components. Check that labels match what you ordered (part number, series/revision).
- Compare to a known good unit. If possible, compare the surplus part to your existing installed unit. PCB layout, component placement, and label formatting should match.
- Test before installing in production. Bench test with a spare power supply and programming cable. Verify basic functionality before putting the part into a critical system.
Building a Relationship with Your Supplier
For ongoing needs, working with a consistent supplier has advantages. They learn what you need, can alert you to parts becoming available, and are more motivated to resolve any issues to keep your business.
The Stanlo Difference: We test all parts before shipping, provide 12-month warranties, and maintain documentation of part condition and testing. Our team can help you identify the right parts for your application and verify compatibility before you order.