Description
Model: Lochinvar KNIGHT XL™ Condensing Boilers - 97% Thermal Efficiency
Fuel: Natural Gas
Weight lbs: 365
Input Btu/hr: 399000
Output Btu/hr: 387000
Notes: Vent size fixed per model
Lochinvar KNIGHT XL™ Condensing Boilers — 97% Thermal Efficiency
The Lochinvar KNIGHT XL Series commercial condensing boilers are engineered for efficiency, reliability, and flexible installation. Each model in this series delivers 97% thermal efficiency and is equipped with advanced control technology, stainless-steel heat exchangers, and factory-assembled components for plug-and-play performance.
Performance & Models
Available in five input capacities ranging from 399,000 to 999,000 BTU/hr. Vent size is fixed per model — 4″ for 400–500 models, 6″ for 650–1000 models. Each unit is configured for Natural Gas operation.
| Model | Input (BTU/hr) | Output (BTU/hr) | Vent Size | Shipping Weight (lb) |
|---|---|---|---|---|
| KBX0400N | 399,000 | 387,000 | 4″ | 365 |
| KBX0500N | 500,000 | 485,000 | 4″ | 377 |
| KBX0650N | 650,000 | 631,000 | 6″ | 456 |
| KBX0800N | 800,000 | 776,000 | 6″ | 484 |
| KBX1000N | 999,000 | 969,000 | 6″ | 567 |
Standard Equipment
Factory Installed
- SMART TOUCH™ control with color display
- Modbus and BACnet® MSTP communication
- 10:1 turndown ratio (modulating burner)
- Stainless steel heat exchanger
- Low NOx premix burner
- Variable-speed combustion fan
- Direct vent-ready with 4″ or 6″ connections
- Built-in gas valve and regulator assembly
In the Box
- Condensate neutralization kit
- Pressure relief valve
- Boiler sensor and vent temperature sensor
- Installation and operation manual
Applications
Ideal for commercial hydronic heating, schools, office buildings, and mechanical system retrofits where high efficiency and dependable operation are essential.
Manufacturer
Lochinvar, LLC — a leading U.S. manufacturer of high-efficiency water heaters, boilers, and hydronic systems.
Manufacturer Reference
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NOTE: We will contact you during order fulfilment to discuss shipping and handling costs for products weighing more than 150 pounds. These costs will be billed separately.