Noritz 40 kW staged-combustion gas combination boilers are aimed at projects that need higher output and more flexible control. Wi-Fi remote control supports real-time adjustments and lets users check operating status easily. These boilers can be applied to heating and hot water systems in private homes, commercial residential buildings, and hotels. Staged combustion also allows the flame to adjust automatically to the load, which helps reduce unnecessary gas use in large-area residential and commercial office heating applications.
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Staged Combustion
Full Combustion
Benefits of Staged Combustion
Heating temperature settings cover 30–80°C, suitable for different space-heating needs
Outdoor flue discharge design helps improve efficiency and reduce energy use
Hot water stays more consistent during multi-point use, even when outlets run at the same time
Noise is kept low, with operation down to 42 dB(A)
Active anti-freeze protection supports stable winter operation
Technical Specifications
Model
GQH-40H1FFAI
Rated heat input
40 kW
Rated heat output
36 kW
Minimum heating output
14 kW
Minimum DHW output
7.8 kW
Minimum start-up flow
2.5 L/min
Thermal efficiency
≥89%
Hot water flow (ΔT = 25°C)
20 L/min
Dimensions (H × W × D)
738 × 510 × 350 mm
Weight
41 kg
Water-flow servo motors
0
Staged combustion
Yes
Circulation pump
1
0.5°C temperature step control
No
Heating temperature range
30–80°C
Hot water temperature range
35–60°C
Noise level (sound power / sound pressure)
≤53 / ≤39 dB
Wi-Fi
Yes
Component Overview
Combustion Fan
A fixed-speed fan supports stable operation and broad compatibility. Reliable start-up performance makes it suitable for higher-load conditions.
Electronic Controller
Provides accurate temperature control and efficient operation. Includes safety protections, convenient smart functions, and fault diagnosis for easier maintenance.
Sealed Combustion Chamber
Side panels use insulating and sound-damping materials to reduce noise and help prevent friction and resonance. H-series gas boilers can operate at noise levels as low as 42 dB(A).*
Noritz Water Pump
Designed for quiet operation to improve comfort. Features built-in self-protection to help reduce fault risk.
Sectional Valve
Supports staged combustion control for finer, more precise flame adjustment.
Five-Stage Heat Exchanger Design
Keeps the unit compact while improving heat absorption. Larger main tubes and a longer heat-exchange path help capture heat more effectively.
Italian SIT Proportional Valve
Precisely regulates gas flow and pressure with fast response. Helps optimize combustion efficiency and reduce energy use.
Expansion Tank
Balances pressure changes in the water circuit and compensates for volume shifts as temperatures change. Helps protect components and supports stable operation.
Component Overview
Installation Dimensions
Applications
Radiator heating: Set within 30–80°C to match different rooms and seasonal needs
Shower comfort: Hot water stays stable, with temperature changes around ±1°C
Floor heating: Quick warm-up in typical use, often about 30 minutes
Kitchen + bathroom: Multi-point hot water use stays steady, so outlets can run together with less interference
NORITZ: From Japan, Serving Customers Worldwide
Noritz is a Japan-based manufacturer with a long track record in hot water and heating technology. With over 70 years of R&D experience, Noritz supplies energy-saving, high-output hot water and heating systems for projects ranging from private residences to commercial buildings. Partners choose Noritz for competitive thermal solutions and reliable global supply chain support.
Staged Combustion
Full Combustion
