Silo Troubleshooting: 6 Common Faults and What to Check Before Calling a Technician

Most silo problems trace back to flow behaviour, sensor accuracy, or discharge equipment wear rather than the structural vessel itself. Here's what to check first for the most common issues.

1. Bridging or Rat-Holing

If material stops discharging or flow becomes erratic, check first whether it's bridging (a stable arch forming above the outlet) or rat-holing (a channel forming through the centre while material at the walls stays stagnant). Both point to the material's flow properties exceeding what the silo's geometry and any aeration assistance were designed to handle — a persistent pattern, rather than an occasional occurrence, usually means the original design assumption about the material no longer holds (a supplier change, moisture variation, or storage time increase can all change flow behaviour).

2. Level Sensor Drift or Inaccurate Readings

Inventory readings that don't match physical checks usually point to sensor fouling (dust buildup on ultrasonic or radar sensors), calibration drift, or a sensor technology mismatched to the material's properties. Clean and recalibrate before assuming sensor failure — buildup is the more common cause.

3. Discharge Valve Not Sealing or Metering Correctly

A rotary valve, slide gate, or butterfly valve that's leaking air, not sealing fully, or metering inconsistently is usually a wear or alignment issue at the valve itself rather than a silo problem. Check valve seal condition and actuator function before escalating.

4. Aeration System Underperforming

If a flat-bottom silo that relies on aeration assistance starts showing flow problems, check aeration pad condition (blinding or wear) and air supply pressure and volume before assuming the material itself has changed — a partially blocked aeration pad delivers less assistance than designed, even though it appears to be running.

5. Venting Issues

Roof vent or pressure relief valve blockage restricts airflow during filling and discharge, which can slow both operations and — more importantly — create a pressure differential safety concern. Venting should be part of routine inspection, not something only checked when a problem shows up.

6. Corrosion or Structural Wear

Visible corrosion, coating degradation, or structural wear at welds and support points needs professional structural assessment rather than a routine maintenance fix — particularly for silos storing corrosive materials or those exposed to weather over many years.

When to Consider a Retrofit

If bridging or rat-holing is a recurring pattern rather than an occasional event, the underlying issue is usually a mismatch between the silo's original design and how the material actually behaves now — worth addressing through added aeration, discharge equipment upgrade, or in some cases bottom geometry modification, rather than living with a permanent workaround.

Spare Parts and Ongoing Support

Discharge valve components, level sensor units, and aeration pads are the parts most likely to need periodic attention. ENZAC provides spare parts supply and scheduled service and maintenance for the silos it supplies, and separately for third-party silos of comparable construction, plus retrofit and upgrade options where a flow or equipment problem doesn't require full replacement.

Review the full Silo / Bulk Storage equipment page for specification detail.