Arburg Error 290: Nozzle Temperature Deviation Beyond Tolerance — Selogica Troubleshooting
Tensile data verified against MatWeb.com database & manufacturer datasheets · Last updated July 2026
Published: 2026-05-31
Arburg Error 290 is a critical interlock alarm on the Selogica control system that prevents screw rotation when the nozzle temperature deviates from setpoint by more than the programmed tolerance band (typically ±15°C for standard processing,...
Arburg Error 290 is a critical interlock alarm on the Selogica control system that prevents screw rotation when the nozzle temperature deviates from setpoint by more than the programmed tolerance band (typically ±15°C for standard processing, ±5°C for precision/high-temperature applications). The interlock protects the screw and barrel from attempting to convey and inject polymer at incorrect viscosity: under-temperature risks cold-start screw damage and excessive screw torque; over-temperature risks polymer degradation, gas generation, and in extreme cases, auto-ignition of decomposed polymer residue.
Diagnostic Protocol for Error 290
Step 1 — Verify the thermocouple: On Selogica, navigate to Diagnostics > Temperature > Nozzle Zone. Observe the actual temperature reading. If it is fluctuating wildly (±20°C in seconds — physically impossible for the thermal mass of a nozzle body), the thermocouple is failing (intermittent open circuit, or moisture in the thermocouple junction). Replace the thermocouple — use Arburg OEM or equivalent Type J or Type K thermocouple with correct bayonet-style connector for the nozzle body. Step 2 — Measure heater band resistance: Disconnect power (Lockout-Tagout). Measure resistance across the nozzle heater band leads — typical values: 20-100 Ω depending on wattage. An open circuit (infinite resistance) confirms a failed heater band. Measure insulation resistance between each lead and the nozzle body (should be >1 MΩ — low insulation resistance indicates moisture ingress or damaged ceramic insulation allowing current leakage to the nozzle body, which also corrupts the thermocouple signal through ground-loop noise). Step 3 — Verify SSR Function: The solid-state relay for the nozzle zone is typically a dedicated SSR (not multiplexed) due to the criticality of nozzle temperature control. With the machine powered and the nozzle zone calling for heat (Selogica shows 'Heating ON'), measure voltage across the SSR output terminals — should be <2 VAC (SSR ON, conducting). If line voltage appears across SSR output terminals when Selogica calls for heat, the SSR has failed open. If line voltage is absent regardless of Selogica heat command, check the DC control signal from the temperature controller to the SSR input (3-32 VDC when heat is ON, 0 VDC when OFF).
Alarm Details
| Alarm Code | 290 |
|---|---|
| Brand / Machine | Arburg |
| Severity | Critical (Interlock — Prevents Screw Rotation) |
| Component | Nozzle Heater Band / Thermocouple / SSR |
| Affected Systems | Injection Unit — Nozzle Zone |
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 Nozzle | |
| Sumitomo Demag Alarm 220 Nozzle |
Frequently Asked Questions
Can I override Error 290 temporarily to finish a run?
Arburg Selogica allows temporary widening of the temperature deviation tolerance band (typically from ±15°C to ±30°C) in the Setup > Temperature > Tolerance menu — but this requires supervisor-level access (password-protected). Widening the tolerance band should be used ONLY as a diagnostic tool to confirm whether the nozzle temperature is genuinely unstable (Error 290 persists even at ±30°C — hardware problem) or borderline (Error 290 clears at ±30°C — suggests a failing heater band, poor thermocouple contact, or PID tuning issue that can be addressed at the next scheduled maintenance). Never widen the tolerance band and continue production without investigating the root cause — nozzle temperature deviation of ±30°C when processing engineering polymers (PEEK, PPS, LCP) with narrow processing windows will produce out-of-spec parts (crystallinity variation, dimensional change, mechanical property loss).
Related Diagnostics & Materials
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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