Gas modular boilers demonstrate significant energy-saving effects: the system automatically adjusts the output of each modular boiler based on temperature changes indoors and outdoors over time, ensuring a constant balance between heat demand and supply. Compared to large single-unit boilers, they achieve approximately 30% energy savings. (1) Single large boilers experience a 12% decrease in annual fuel utilization efficiency due to heat load fluctuations; (2) Single large boilers incur a 7% standby heat loss during heat load fluctuations; (3) Single large boilers suffer a 4.5% increase in chemical combustion loss during heat load fluctuations; (4) The forced-draft combustion method of single large boilers increases electricity consumption by 2%; (5) Modular boilers equipped with ventilation regulators save 2% on fuel costs; (6) The integration of an intelligent control system with modular boilers reduces energy consumption by 2.6%. Vandelli gas modular boilers are safe and reliable. In open installation systems, the boiler's hydraulic system operates at atmospheric pressure and includes multiple comprehensive safety protections: flameout protection, dry-burn protection, freeze protection, low-water-level protection, automatic exhaust protection, overheat protection, and leakage protection. In closed installation systems, the sealed water circuit operates under a pressure of 0.05–0.3 MPa. In addition to the safety features of open systems, closed systems also include: pressure expansion protection, low-water-pressure protection, and a safety pressure relief device for high-pressure conditions. Compared to traditional single-unit gas boilers, Shaanxi Deli direct-fired gas modular boilers offer the following advantages: - High autonomy: The heating effect is customizable based on the user's actual needs, and the system can provide domestic hot water year-round. - Long service life: The cast iron heating sections are designed for a 50-year lifespan, ensuring reliability and user satisfaction. - Redundant operation: The system remains operational even if one boiler fails, as other units continue functioning normally. - Low maintenance rate: Modular gas boilers require significantly less maintenance than oil, coal, or single-unit gas boilers.