HTS Hauck – WHI Wall Hugger Invisiflame® Gas Burner

Overview

The Honeywell Hauck WHI Wall Hugger Invisiflame® is a direct-fired, air-staged gas burner engineered for industrial furnace applications requiring even heat distribution with no flame impingement and ultra-low NOx emissions. The burner’s flat flame profile hugs the furnace wall throughout the firing range, enabling placement close to the load while maintaining uniform temperature distribution by radiation from the furnace walls and roof.

The WHI operates in two modes: a standard “Firing” mode for cold startup and operation below 1,600°F (870°C), and Invisiflame® mode for ultra-low NOx operation above 1,600°F (870°C). Transitioning between modes is accomplished via a motorized switching valve. Standard capacity ranges from 2 to 6 million Btu/hr (580 to 1,760 kW) depending on air preheat temperature.

Features & Benefits

• Ultra-low NOx emissions of 20 ppm or less — achieved through three-staged air injection design
• Low excess air operation at 5% — maximizes fuel efficiency and reduces operating costs
• Flat flame profile throughout the entire firing range — even heat distribution with no flame impingement on the load
• Turndown ratio of approximately 10:1 on natural gas — wide operating range for process flexibility
• Low CO emissions including during cold start — reduces emissions across all operating conditions
• Compatible with cold or preheated combustion air up to 900°F (480°C) — supports recuperative systems
• Direct spark or pilot ignition options available
• Stable operation at ratio in cold furnace — reliable low-temperature startup performance
• Adjustable flange for ease of installation — simplifies field mounting and alignment
• Single air and fuel connections — simplified piping and installation
• Available in round or square tile versions — accommodates various furnace wall configurations
• Dual operating modes (Firing and Invisiflame®) via motorized butterfly valve — seamless transition controlled by furnace temperature

Technical Specifications

• Capacity range: 2 to 6 MM Btu/hr (580 to 1,760 kW) depending on air preheat
• Maximum furnace operating temperature: 2,500°F (1,370°C)
• Combustion air preheat: ambient to 900°F (480°C)
• Burner static inlet air pressure (high fire): 20.9 in. w.c. (5,200 Pa)
• Turndown: approximately 10:1 on natural gas
• Firing mode: required for furnace temperatures below 1,600°F (870°C)
• Invisiflame® mode: suitable for furnace temperatures above 1,600°F (870°C)
• Fuel: any clean industrial fuel gas with HHV of 500 Btu/ft³ (19.7 MJ/nm³) or greater
• Flame detection: UV scanner in Firing mode
• Tile options: round or square
• Mounting orientation: roof, wall, or bottom of furnace
• NOx emissions: 20 ppm or less
• Excess air at high fire: 5%

Applications

• Direct-fired industrial furnaces requiring even heat distribution
• Applications requiring ultra-low NOx emissions compliance
• High-temperature furnace processes above 1,600°F (870°C) using Invisiflame® mode
• Furnaces with load proximity requirements where flame impingement must be avoided
• Recuperative systems with preheated combustion air
• Applications requiring wide turndown capability with stable low-fire performance
• Roof-fired, wall-fired, and bottom-fired furnace configurations

Models / Configurations

• WHI-140 – Small series, ambient air (60°F); max input 2.4 MM Btu/hr in Firing mode, 2.0 MM Btu/hr in Invisiflame® mode at 20.9 in. w.c. static air pressure
• WHI-240 – Small series, preheated air (900°F); max input 1.5 MM Btu/hr in Firing mode, 1.2 MM Btu/hr in Invisiflame® mode
• WHI-160 – Large series, ambient air (60°F); max input 4.9 MM Btu/hr in Firing mode, 4.5 MM Btu/hr in Invisiflame® mode
• WHI-260 – Large series, preheated air (900°F); max input 3.0 MM Btu/hr in Firing mode, 2.8 MM Btu/hr in Invisiflame® mode
• Round tile – Available on all series; specify at time of order
• Square tile – Available on all series; specify at time of order
• Direct spark ignition – Standard ignition option
• Pilot ignition – Alternative ignition option; ZMI ionization pilot available

WHI Wall Hugger Invisiflame® Accessories

The WHI platform requires an Invisiflame control valve and motorized actuator for operation in furnaces below 1,600°F. Spare parts are documented in the WHI parts list (WHI-6).

• IC20 Butterfly Valve Actuator – Motorized actuator for the Invisiflame control valve; required for low-temperature furnace startup and mode switching
• ZMI Ionization Pilot – Spark-ignited gas pilot assembly for pilot ignition configuration
• UV Scanner (P/N 84333120) – UV flame detection scanner for Firing mode operation (WHI-140/240 and WHI-160/260)
• Square Tile Assembly – P/N 405158x (WHI-140/240), P/N 404632x (WHI-160/260)
• Round Tile Assembly – P/N 405864x (WHI-140/240), P/N 404788x (WHI-160/260)
• Air Cooled Spark Igniter Assembly – P/N 405162×001 (WHI-140/240), P/N 404637×001 (WHI-160/260)
• Spark Ignited Gas Pilot Assembly – P/N 405843 (WHI-140/240), P/N 404858 (WHI-160/260)

Documentation