Arburg Error 320: Barrel Heating Control Failure - Troubleshooting Guide
Tensile data verified against MatWeb.com database & manufacturer datasheets · Last updated July 2026
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
Verify all electrical connections to the affected component. Check for loose wires, burnt connectors, or signs of arcing. Measure voltage at the component terminals.
Look for physical damage, corrosion, or wear. For heating bands: check for hot spots (discoloration). For sensors: check for damaged cables or contamination on the sensing surface.
For thermocouples: measure resistance (should be 2-10 ohms, not open circuit). For heating bands: measure resistance against the nameplate rating. For relays: test coil resistance and verify switching with a test signal.
Order the OEM replacement part (see OEM Parts table above). After replacement, run a full heat-up cycle and verify the alarm does not re-trigger. Document the replacement in the machine log.
OEM Replacement Parts
| Part Name | OEM Part Number | Est. Price |
|---|---|---|
| Arburg OEM Heating Band | AR-220.xxx-HB | $400-800 |
| Arburg Thermocouple Fe-CuNi | AR-220.xxx-TC | $100-220 |
| Arburg Solid State Relay | AR-SSR-50A | $180-350 |
| Arburg Selogica Controller Module | AR-SEL-CPU | $2,500-4,500 |
Prices are estimated US market ranges. Contact your OEM distributor for exact pricing. {zone} = zone-specific variant.
Same Alarm on Other Machine Brands
If you operate multiple injection molding machine brands, the same fault may appear under different alarm codes:
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.
Related Diagnostics & Materials
Netstal Alarm 102: Heating Zone Temperature Out of Range...
Netstal Alarm 102 occurs when the actual temperature of a specific heating band in the injection barrel deviates...
Engel Alarm 405: Screw Recovery Time Exceeded - Diagnostics & Fix
Engel Alarm 405 is generated by the CC300 controller when the screw recovery (plastication) time exceeds the maximum...
Netstal Alarm 301: Mold Protection Force Exceeded -...
Netstal Alarm 301 is one of the most critical safety alarms in injection molding—it triggers when the clamping unit...
Sumitomo Demag Alarm 220: Clamp Force Not Reached -...
Sumitomo Demag Alarm 220 triggers when the NC5 (or NC5 plus) controller detects that the actual clamping force...
KraussMaffei Alarm MC45: Injection Pressure Limit...
KraussMaffei Alarm MC45 is generated by the MC6 controller (KM's latest-generation control platform) when the...
Wittmann Battenfeld Alarm B6: Ejector Position Fault -...
Wittmann Battenfeld Alarm B6 triggers on the Unilog B8 (or B6/B6P) controller when the ejector system fails to reach...
Arburg Error 290: Screw Rotation Speed Deviation -...
Arburg Error 290 is triggered by the Selogica controller when the actual screw rotation speed (measured by the screw...
Engel Alarm 510: Hydraulic Oil Temperature High -...
Engel Alarm 510 is generated by the CC300 controller when the hydraulic oil temperature exceeds the user-programmed...
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