26 | Plant & Works Engineering www.pwemag.co.uk October/November 2025 Energy & Environmental Management Focus on: Boilers, Burners & Controls At heart, a boiler only needs to do a few things: regulate temperature or pressure, control the fuel and air to the burner, maintain water level and protect against unsafe conditions. For years, these functions were handled mechanically or by simple relay logic. Many plants still run on that basis, but modern systems are now tying everything together - boilers, burners and auxiliary equipment - through programmable logic controllers (PLCs), burner management systems (BMS) and plant-wide monitoring. Integration is not just about adding electronics; it’s about making sure the entire system works as one. A BMS no longer simply lights a flame; it manages purging, ignition, valve sequencing, flame detection and safe shutdowns. Linked to a PLC or distributed control system (DCS), it can coordinate multiple boilers, share loads and react automatically to changing demand. When done properly, this means smoother operation, fewer interventions and better efficiency. Where these systems succeed, it’s because they’re designed with purpose and clarity. The detail matters: sensor placement, tuning of control loops, the logic of fault handling. These are not jobs to be left until after installation. Good control design starts with understanding how the plant behaves and what operators need day to day. Older sites often face the opposite problem: a patchwork of equipment that doesn’t talk to each other. A 20-year-old boiler may still run well, but its controls might be a tangle of relays, while a newer burner uses a digital controller on a different platform. Feed-water systems might have yet another control scheme. The result can be pressure swings, temperature overshoot and short-cycling because each part is reacting independently. Integrating these elements can make a big difference. When the BMS links into the site PLC, boilers can be sequenced intelligently so each runs near its efficient load. Feed-water control can anticipate steam demand instead of simply chasing it. Operators can see everything on a single screen, compare performance, and act before a small issue becomes a fault. There’s still a balance to be struck. Overautomation can create as many problems as under-automation if systems become too complex to maintain. Controls should be logical, fail-safe and understandable. The people running the plant should be able to trace what’s happening without scrolling through pages of code. Simple diagnostic displays, clear alarms and manual override options are essential. Replacing all controls in one go is often unrealistic, especially where downtime is costly. A phased approach tends to work better: upgrade the burner management first, then link it to a PLC, then add data logging and remote monitoring. Each stage can be tested and learned before moving on. Every upgrade should reflect the site’s priorities. If efficiency is key, consider oxygen-trim control, variable-speed fans or flue-gas monitoring. These can save fuel and reduce emissions, but only if sensors are reliable and control loops are tuned correctly. If reliability is the concern, invest in redundancy - dual sensors, backup controllers and robust communication links. Modern systems also make better use of data. Continuous monitoring of combustion efficiency, boiler load, feed-water temperature and fuel flow can highlight trends that would otherwise go unnoticed. A burner drifting off its setpoint or a boiler underperforming can be spotted early. Maintenance can then be targeted rather than routine. Remote access is another growing feature. Engineers can review data, adjust setpoints or diagnose faults without being on site. This saves time but brings new cyber-security responsibilities. Industrial networks must be protected with secure connections, firewalls and controlled access — these are now part of standard engineering practice rather than afterthoughts. Skills challenge Skills remain a challenge. Controls engineers now need to understand combustion as well as programming. Maintenance technicians must be In many industrial plants, boilers still sit at the centre of operations - reliable, familiar and often overlooked until something goes wrong. They produce heat or steam, driven by burners and guarded by layers of safety devices. But as industrial automation advances, the way these systems are controlled is changing fast. PWE reports. Making systems work together comfortable with software as well as mechanical checks. Training and documentation are therefore critical. The best installations are those where operators are involved from the start, helping to shape the interface and understand its logic. The aim of integration is simple: safer, more efficient and more reliable operation. A welldesigned control system keeps boilers operating near their optimum point, minimises fuel waste and reduces emissions. It also provides confidence that safety functions will work as intended. The biggest pitfalls usually come from neglecting fundamentals. Controls can only manage what they measure. If sensors are poorly located or maintained, no amount of automation will help. Regular testing of safety interlocks, calibration of transmitters and inspection of flame scanners should remain standard practice. Human input is just as important. Operators and engineers know the quirks of their plant, involving them in control design leads to more practical systems and better engagement. People are more likely to trust and use a control interface when it reflects how they actually work. The direction of travel is clear, more automation, greater connectivity and stronger focus on carbon and energy performance, but the fundamentals remain the same. A control system should be transparent, maintainable and adaptable, not complicated for its own sake. That means clear logic diagrams, proper documentation, meaningful alarms and sensible manual overrides. It means designing for flexibility so that if a burner or fuel source changes, the system can adapt without a major rewrite. Industrial boiler control has evolved from gauges and handwheels to integrated digital systems, but the principle is unchanged: keep the process stable, safe and efficient. Integration, done properly, supports the engineer rather than replacing them. It handles routine adjustments, provides good information and allows better decisions.
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