Arburg Error 320: Barrel Heating Control Failure - Troubleshooting Guide
Published: 2026-05-26
Arburg Error 320 is a critical interlock alarm triggered when the Selogica controller detects no current flow to one or more heating zones despite the relays being commanded ON. This diagnostic logic differentiates Error 320 from a simple...
Arburg Error 320 is a critical interlock alarm triggered when the Selogica controller detects no current flow to one or more heating zones despite the relays being commanded ON. This diagnostic logic differentiates Error 320 from a simple temperature deviation alarm—the controller is specifically detecting an electrical fault (open circuit, blown fuse, or failed SSR) rather than a thermal control issue.
The most common root cause sequence: (1) polymer leakage (drool) from a worn nozzle tip or check ring runs down the barrel and carbonizes on the heater band terminals, (2) the carbonized polymer creates a conductive path that shorts the heater band to ground, (3) the resulting current surge blows the semiconductor fuse protecting that SSR circuit, and (4) the Selogica controller detects zero current flow when commanding the SSR ON, triggering Error 320.
For Arburg ALLROUNDER machines equipped with the Selogica Direct controller, the diagnostic screen will indicate which heating circuit has failed and the phase current measured at the time of fault (0.0 A confirms open circuit; normal reading 8-15 A per zone depending on machine size).
Alarm Details
| Alarm Code | 320 |
|---|---|
| Brand / Machine | Arburg |
| Severity | Critical (Interlock) |
| Component | Solid State Relay / Heating Circuit |
| Affected Systems | Heating Controller / Selogica |
Troubleshooting Protocol
Identify which zone/component triggered the alarm. Record the error code, timestamp, and any measured deviation values shown on the diagnostic screen.
Power down the machine and follow Lock-Out Tag-Out procedures. Visually inspect the affected component for physical damage, loose connections, polymer leakage, or carbonized material.
Using a multimeter, check resistance/continuity on the affected circuit. Verify SSR functionality and fuse integrity. Compare readings to OEM specifications.
Replace the failed component with an OEM-approved part. Do not substitute with generic equivalents unless validated for the specific machine model and operating conditions.
Restart the machine, verify the alarm is cleared, run a test cycle, and document the root cause, repair performed, and parts replaced in the machine maintenance log.
Equivalents & Cross-References
| Equivalent / Alternate | Action |
|---|---|
| Netstal Alarm 102 | |
| Engel Alarm 405 |
Frequently Asked Questions
What is the troubleshooting sequence for Arburg Error 320?
(1) Check the Selogica diagnostic screen to identify the faulted zone. (2) Power down the machine and LOTO (Lock-Out Tag-Out). (3) Remove the heater band cover from the faulted zone and inspect for polymer leakage/drool carbonization on band terminals—this is the root cause in ~60% of cases. (4) Measure heater band resistance with a multimeter (typical values: 30-50 Ω for a 230V 1.2kW band; open circuit = failed band). (5) If the band passes the resistance check, inspect the SSR and its semiconductor fuse (Arburg part number varies by machine generation; check electrical schematic for the correct rating). (6) Replace the failed component, clean all carbonized polymer from the barrel surface, and verify proper nozzle sealing before restart.
Does Error 320 cause any risk of barrel or screw damage?
Error 320 itself does not directly damage the barrel or screw—it is a heating circuit electrical fault detected by the controller. However, the root cause (polymer leakage carbonizing on heater bands) indicates a nozzle or check ring seal failure. If not addressed, continued polymer leakage will (1) carbonize on the barrel surface causing localized hot spots and uneven heat transfer, (2) potentially enter the heater band terminal box causing a phase-to-ground short and risk of electrical fire, and (3) indicate a worn nozzle tip/seat that will progressively worsen, causing shot weight variation and part quality issues.
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References & Industry Standards
- ASTM International. Standard Specifications for Engineering Plastics & Thermoplastics. astm.org
- UL Prospector. Plastics & Elastomers Material Database. ulprospector.com
- MatWeb. Material Property Data for Engineering Thermoplastics. matweb.com
- ISO 1043. Plastics — Symbols and Abbreviated Terms. iso.org