Low Water Cut-off Steam Boiler – Dry Boil Prevention

All our steam boiler are equipped with a low water cut-off (LWCO) system. It is our responsibility to ensure the safe operation of the boiler.

The low‑water cutoff is a fail‑safe electrical control that prevents burner operation when water falls below a safe threshold. Two primary LWCO designs are used:

• Float‑Type LWCO
  A buoyant float within a chamber tracks the water level. As the water drops, the float descends and actuates a switch to shut down the burner when the level falls too low. Float‑type devices can be external (with a sight glass) or internal, offering visual confirmation of water level in the former.

• Probe‑Type LWCO
  Conductivity probes inserted into the boiler complete an electrical circuit when submerged. If water drops below the probe, the circuit breaks and the boiler is automatically shut off. Probe‑type LWCOs react faster to water‑level changes but require maintenance to prevent scale from insulating the probe.

Both types work in conjunction with the Loop piping arrangement to guard against boiler dry‑fire and potential BLEVEs (Boiling Liquid Expanding Vapor Explosions), a paramount concern in steam systems.

Automated Scale Detection

Scale (mineral deposits) reduces heat transfer efficiency and can trigger localized overheating. Our boilers integrate a colorimetry‑based hardness detection system:

• In‑Line Hardness Measurement
  A reagent cartridge periodically mixes with boiler water; a photometric sensor measures turbidity changes to quantify hardness.

• Real‑Time Alerts & Dosing
  If hardness exceeds preset limits, the system sounds an alarm and can automatically dose anti‑scaling chemicals. All events are time‑stamped in the PLC log for historical analysis.

This continuous approach prevents scale accumulation before manual inspection or shutdown becomes necessary, preserving thermal efficiency and extending maintenance intervals.

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Fault Alarm & Logging

Our PLC acts as the brain of the boiler, keeping tabs on key readings and handling alerts:

• Sensor Hub
  It gathers live data from water‑level gauges, temperature and pressure probes, and conductivity meters.

• Instant Alerts
  If it spots anything unusual—like a fast drop in water level or a sudden pressure rise—it immediately sounds an alarm. Even make emergency treatment. Prevent accidents from happening.

• Detailed Records
  Every alert, shutdown, and parameter change is time‑stamped and stored, so you can review what happened and plan maintenance before issues grow.

• Off‑Site Alerts
  Critical alarms can be sent over your network or cellular link straight to your team, so problems get attention even if no one is on site.

PLC‑Based Control & Integration

Beyond safety interlocks and logging, the PLC automates daily boiler operation:

• Start/Stop Sequences
  Soft‑start burner control and staged modulation maintain stable steam pressure while minimizing thermal stress.

• Feedback Loops
  Level controls adjust feed‑water pumps to match steam demand; economizer bypass dampers modulate to optimize combustion efficiency.

• Human‑Machine Interface (HMI)
  A touchscreen panel displays system status, sensor readings, alarm histories, and allows on‑the‑fly parameter adjustments.

This tight integration of safety devices, monitoring sensors, and automated control delivers a boiler solution that is both high‑performance and inherently safe.

Conclusion

Our boiler uses proven low‑water cutoffs alongside continuous scale monitoring and PLC control. This means fewer service interruptions, lower fuel consumption, and dependable steam—whether for industrial processes or heating.