Cities nowadays use a large share of energy for heating, while limited space, existing infrastructure, and installation constraints strongly influence which heating technologies can be used.

For manufacturers of heating solutions, this means that flexibility is essential. Systems must be able to support different heating sources and integrate into existing installations, rather than relying on a single predefined heating concept.

The focus of this project was on integrating an existing third-party gas boiler into the client’s heating system.

The goal was for the gas boiler to behave as a native subsystem of the client’s platform, fully monitored, controlled, and supervised using the same internal mechanisms as other heating components. That will allow the client to offer a wider range of heating options without redesigning their core system.

The Challenge

The main challenge was the integration of two conceptually different systems.

Third-party gas boilers operate using their own internal logic and communication model, while the interaction with the outside world is via Modbus over RS485.

The client’s platform, on the other hand, relies on the custom communication protocols, which enable interaction between system modules with well-established behavior. This platform is also designed with custom-tailored logic.

This required more than basic approach:

• The gas boiler’s behavior had to be precisely understood and mapped to the client’s platform
• Its operational states and fault conditions had to be translated into the client’s internal logic
• The system needed to interact with the boiler in the same way it does with native subsystems

A notable constraint was the absence of a physical gas boiler on our side. All hardware testing was performed at the client’s premises.

Instead of treating this as a limitation, the project was structured around:

• clear and continuous technical communication with the client
• transparent insight into the system behavior during testing
• fast feedback loops for detected issues and test results

This approach allowed development to progress reliably despite limited direct hardware access.

Our Contribution

Development

Our team was responsible for the software integration layer and did the following:

• Proactive review and refinement of requirements, including clarification of edge cases
• Design and implementation of a reusable software module representing the gas boiler within the system
• Adaptation to the Modbus communication (Modbus over RS-485)
• Full integration with the existing system architecture
• Development of a dedicated state machine for reliable control of gas boiler operating modes
• Robust error handling for fault detection and propagation

Starting from an initial, limited set of requirements, continuous analysis and collaboration with the client led to:

• Identification of additional system capabilities
• Gradual expansion of functionality
• Dynamic change of the requests

Testing Strategy

Due to the lack of physical hardware, testing required special attention.

We developed a custom test environment to emulate gas boiler behavior.
This allowed validation of system behavior before and during on-site testing.

Automated test scripts, consisting of an emulator implemented in Python, drove the developed software module through real-world scenarios for behavior inspection.

The custom-developed software test framework was then used to check and verify the internal functionality of the module, its edge cases and faulty conditions.

This significantly reduced integration risk and ensured predictable system behavior.

Results

The project outcome is a stable and reliable system that:

• Communicates consistently with third-party gas boilers
• Enables basic monitoring and control
• Supports gas-based heating
• Can work with gas boilers from different manufacturers with minimal adaptation
• Provides a solid foundation for more advanced heating system control in future iterations

By enabling support for third-party gas boilers, the client significantly expanded the applicability of their system:

• Support for gas-based heating, particularly relevant for urban and densely populated environments
• Compatibility with existing installations, avoiding large infrastructure changes
• Access to markets where solid fuel heating is impractical or restricted
• A cleaner heating option compared to previous concepts, enabled by gas combustion