Boiler control

A customised boiler control system plays a crucial role in ensuring the safe, reliable and cost-effective operation of a hot water boiler system.

The safety requirements set out in the relevant regulations governing the installation and safe operation of boiler systems must therefore be observed. However, in addition to safety and reliable operation, more advanced energy management requirements – such as data recording and the continuous optimisation of boiler operation – are also important today. Furthermore, it should be possible to manage the entire operation via a central control system, as only through internal communication between heat consumers and heat generation can an operating mode be achieved that is optimised for the overall efficiency of the system.

The safety requirements set out in the relevant regulations governing the installation and safe operation of boiler systems must be observed. In addition to safety and reliable operation, more advanced energy management requirements – such as data recording and the continuous optimisation of boiler operation – are also important today. Connection to a central control system or an energy management system is crucial for achieving operation that is optimised from an overall economic perspective.

The functions of a boiler control system include:

• Safety functions
• Control functions
• Operating and fault messages
• Data collection and analysis
• Control system integration

Since 2001, Bosch Industriekessel GmbH, a pioneer in the field of boiler manufacturing, has been fitting PLC-based control systems as standard in shell boiler systems. This concept proved to be extremely successful on the market and has now become standard practice. The ongoing development of control systems and intuitive operation ensure a high level of transparency and connectivity in the Industry 4.0 environment.

Product: System control SCO

Control systems

Modern control systems for boilers and boiler houses now largely rely on tried-and-tested industrial hardware from the field of programmable logic controllers. These devices handle all control and regulation functions for the boiler or boiler system and are capable of communicating via bus systems or networks with other control systems, such as burner management systems, separate control systems for boiler house modules and higher-level control systems. Due to the high reliability requirements, the safety chain is generally still implemented using conventional contactor and relay technology.

The control software is stored entirely on a micro memory card, which means that there is no need for backup batteries or EPROMs to protect against voltage failures. The units are space-saving and modular in design, and are screwed together on a profile rail to form a robust, electromagnetically compatible assembly. As an option, additional units such as extra inputs and outputs or a communication processor – for example, for Ethernet – can be combined as required to connect to the central control system. Another option is an Industrial Ethernet network for connecting multiple control modules or for preparing for MEC Remote access.

Software function modules that are specifically tailored to the respective boiler and boiler system control systems and are factory-tested ensure that the complex and stringent requirements for safe boiler operation are met. This enables customers to use a wide variety of systems, in which the individual software modules have already been extensively used and tested in practice. Special custom programming is only carried out in very rare cases.

BCO boiler control

A graphical TFT display with a touch-sensitive surface is used for display and operation. Thanks to its exceptionally long service life, high brightness and high contrast, it is ideally suited to the toughest industrial applications. A backup of the graphical menu structures, as well as the notifications and the process value archive, is stored on an SD card that is inserted into the control unit.

The touchscreen displays are designed to be user-friendly and allow users to intuitively access the available control and regulation functions, as well as to view or make limited adjustments to actual and setpoint values.

Even in its basic configuration, the BCO boiler control system displays a wide range of operating states, operating data and measured values for the boiler system. These include, for example, the operating hours of the boiler and the burner, and the number of times the burner has been started. In addition, all set switching points, switching differentials and limit contacts can be displayed. Key process data is stored on the memory card of the boiler or system control unit at specified intervals. The archive operates on a rolling basis: As soon as the storage capacity is reached, the oldest process data is deleted and the most recent data is archived. The latest data can then be viewed on the displays in the form of curve displays. In addition, the customer service team can retrieve data from the process value archives.

Functions in hot water boiler systems
Basic functionality of the BCO boiler control system for hot water boiler systems
In addition to the basic functions for power control, temperature control via RTS and the safety chain, which are standard features of every modern hot water boiler, the BCO boiler control system can be expanded with the following additional options and functions:

• Automatic start-up from a cold start
• Measurement of the flue gas temperature for boilers with flue gas heat exchangers
• Measurement of the mass flow rates (fuel, heat quantity, etc.)
• Keep-warm mode – normal operation
• Display of operating hours, start frequency, number of cold starts over time
• Detection of unfavourable start-up conditions
• Detection of soiling on the water and flue gas side or unwanted condensation
• Generation of maintenance messages as required
• Display of the boiler load profile over time
• Connection to higher-level control systems
• Remote maintenance via MEC Remote
• Connection to a central control system

Condition Monitoring (CM)

CM enables customers to monitor both the efficiency and the correct operation of their system. To this end, the system data is analysed, evaluated and presented clearly using a traffic light system.

Control 8000

The Control 8000 can be used to control various heating systems in residential properties and large buildings. The modular technology allows for customisation to suit specific projects.

• Customer-specific control thanks to flexible, extendable functional modules
• Intuitive operation via a colour touch screen
• Easy integration into the building management system
• Versatile integration options and easy installation
• Secure remote connection for outstanding availability and control regardless of location

The Control 8000 is mainly used for smaller commercial applications with boilers up to around 800 kW. For larger boilers such as the Bosch UT-L, the Control 8000 is an option when it comes to simply controlling burner modulation and maintaining the return temperature maintenance. It should be noted that the Control 8000 is not designed as a “plug-and-play” system. The system circuit diagram, the control cabinet containing all power components, and the wiring for the sensors and actuators are to be provided by the client. For fully integrated solutions, we therefore recommend our range of industrial boiler control systems.

In use

Each of the Bosch control systems is suitable for different applications but which one is the right choice for which boiler system? A few examples illustrate the benefits of hot water boiler control systems and their potential applications.

Example 1: District heating supply using two UT-HZ hot water boilers, each with a capacity of 25 MW, and associated components

The high complexity and enormous scale of a district heating system call for a project-specific control system, for example for a district heating system comprising two Bosch UT-HZ boilers, each with a capacity of 25 MW, and associated components. Both hot water boilers are controlled by the customised BCO. The SCO central system control consolidates the data from the connected boiler control systems and components. By dynamically and automatically switching between the boilers, it ensures maximum durability and efficiency. Custom programming allows the control system to be tailored to project-specific requirements. Furthermore, the SCO transmits the collected data to the system’s control technology via standard protocols. Remote access allows you to monitor the system at any time and from anywhere, while the MEC Optimize smart solution continuously optimises system efficiency.

Example 2: Three UT-M hot water boilers for process heat in production and for heating the associated buildings

Many production sites require hot water for process applications and for heating production halls. The heat generated is often used to heat the associated office and logistics buildings as well. In this application, which involves three UT-M hot water boilers, each delivering 16 MW of heat output, the compact CWC is used not only to control the individual boilers but also as an intelligent sequence control. The boilers are regulated according to the heat demand of the consumers, ensuring they operate at optimum efficiency. CWC also carries out the safety measures and ensures optimum inlet temperature control for the existing flue gas heat exchangers on a boiler-by-boiler basis. Preconfigured, standard protocols enable connection to central control and automation systems. With the MEC Remote remote access feature, system data can be viewed at any time. Further benefits include optional SMS or e-mail alerts in the event of a fault as well as unattended operation for up to 72 hours, in accordance with the relevant legislation.

SCO system management system

The SCO integrates control systems for Bosch boilers and associated modules into a comprehensive management system, opening up a wide range of new possibilities.

The SCO (System Control) is our efficient, programmable system management system for multi-boiler systems and associated boiler house components. The intelligent control system allows the boilers to be connected in series, ensuring greater durability, a more reliable supply and more efficient operation of the system. In doing so, it switches the boilers on and off dynamically depending on the current demand from the consumers. Communication with higher-level visualisation and control systems can be carried out using various control system protocols, such as Profinet IO, Modbus TCP/IP and BACnet. The optional remote connection via MEC Remote allows the system to be monitored from anywhere.

Information about the sequence control

At a glance

• System management system for controlling multi-boiler systems and associated boiler house components
• Easy connection to higher-level visualisation and control systems
• Integrated monitoring and protection functions to prevent faulty operation
• Extensive storage of operating parameters and operating signals
• Optional remote connection via MEC Remote: User interface visualisation
• Intuitive operation thanks to the use of graphical symbols on the touchscreen display

MEC Remote

With MEC Remote, operators can conveniently and safely access their hot water and steam boiler systems from off premises. The entire boiler and system control system can be visualised via standard Internet-enabled devices.

MEC Remote is the ideal solution for operations:

• Where supervisory staff cannot be on-site at all times
• With single-boiler or multi-boiler systems subject to supervision
• With on-call duty at weekends

An overview map allows the operator to monitor all of their systems at the same time. The secure remote access software mirrors the user interface of the control and enables the operator to view the relevant data.

Effective service support
On request, Bosch experts can carry out advanced parametrisation, programming (PLC) and fault analysis directly via remote access. If components fail, the service experts can already narrow down the cause using remote analysis and travel to the site with the appropriate equipment and spare parts. This results in optimised service costs and increased system availability.

Secure remote access
One of the most important requirements for remote connectivity is that it must be as secure as possible. This is ensured by the sophisticated role-based system, which controls access rights and the visualisation levels that are made available. The remote access system itself features a multi-layered security approach. The external data connection can be enabled or disabled at any time in the boiler house using a key to access the hardware. In addition to logging in with a user name and password via an encrypted connection (https), a mobileTAN procedure is used.

Connection options

• DSL router
• The operator’s own network
• Mobile network

Scope of services

• User interface visualisation
• Navigation through the control
• Parametrisation and programming by Bosch Service via the service access

At a glance

• Access to operating data, at any time from anywhere
• An overview of boiler systems at all sites
• Quick, convenient and cost-effective monitoring of the system data
• Secure transmission thanks to a multi-layered security approach
• Remote support from Bosch Industrial Service available on request