HTS Eclipse – Linnox ULE Line Burner Series

Overview

The Linnox ULE (Ultra Low Emissions) is a pre-mix line style burner engineered for direct and indirect fired air heating applications where heat distribution uniformity, minimal emissions, and reliable turndown are critical. Developed by Eclipse, a Honeywell Thermal Solutions brand, the Linnox ULE operates on a high-excess-air pre-mix combustion principle that suppresses flame temperatures while internal recirculation geometry maintains stable combustion across the full operating range.

The Linnox ULE series is available in Straight ULE and Tee ULE configurations, allowing single or multi-row duct installations. NOx emissions in undiluted flue gas are less than 15 ppm at 3% O₂ at nominal input — establishing the Linnox as a benchmark low-emissions line burner. Eclipse designs custom Linnox ULE systems to meet specific application requirements including capacity, duct geometry, and regulatory compliance.

Features & Benefits

• Ultra-low NOx emissions — less than 15 ppm at 3% O₂ at nominal input, making it compliant with stringent air quality regulations
• Ultra-low CO emissions — less than 100 ppm at 3% O₂, supporting clean combustion throughout the operating range
• High-excess-air pre-mix combustion with internal flame recirculation — keeps flame temperatures low for stable, uniform heat output
• 10:1 turndown ratio (8:1 also available) — enables wide modulation range while maintaining stable combustion and low emissions
• Excellent heat distribution and temperature uniformity — linear burner geometry ensures consistent heat across the full duct width
• Up to 4 burner rows in a single duct — Tee ULE configuration scales total input up to 45 MM Btu/h
• Wide input range per module — 90 to 2,700 kBtu/h (26 to 791 kW) per 300 mm module length
• Direct spark ignition — simple, reliable ignition without pilot burner requirements
• Robust ratio regulator-controlled gas/air ratio — Eclipse-supplied ratio regulator maintains accurate fuel-air mixture across the turndown range
• Stainless steel housing — corrosion-resistant construction suited to demanding air heating environments
• Modular design — standard lengths up to 9 ft (2,700 mm); longer lengths available as engineered orders

Technical Specifications

• Combustion method: High-excess-air pre-mix with internal flame recirculation
• Input capacity: 90 to 2,700 kBtu/h per module (26 to 791 kW per 300 mm)
• NOx emissions: <15 ppm at 3% O₂ at nominal input (undiluted flue gas)
• CO emissions: <100 ppm at 3% O₂
• Turndown ratio: 10:1 standard; 8:1 alternate configuration
• Air pressure requirement: 20 in wc (50 mbar) at burner inlet at maximum input
• Airflow direction: Process air must flow parallel to burner flame — no cross-flow permitted
• Standard burner length: Up to 9 ft (2,700 mm); longer lengths as engineered orders
• Number of rows: Up to 4 burner rows in a single duct (Tee ULE)
• Fuel type: Natural gas standard; alternative fuels require Eclipse consultation
• Ignition: Direct spark ignition
• Flame detection: UV scanner only — no flame rod option
• Control actuator: Modulates air butterfly valve
• Control motor: Rotation ≤2 rpm (≈30 s/90°); torque ≥25 in-lb (2.8 Nm); 90° stroke; continuous or high/low modulating; reversible
• Ratio control: Eclipse-supplied ratio regulator required
• Housing material: Stainless steel; standard steel plate for sizes above AB600L (consult Eclipse for upstream temperatures above 500°F)
• Mounting: Mounting plate for installation into process air duct (insulated or non-insulated)
• Standards applied: EN 746-2:2010; EN ISO 12100:2010

Applications

• Direct fired air heating systems requiring ultra-low NOx and CO emissions
• Indirect fired air heating with stringent temperature uniformity requirements
• Industrial dryers and ovens where linear heat distribution is critical
• Dairy and food processing heating applications
• HVAC make-up air and process air heating systems
• Applications requiring wide turndown with stable combustion at low firing rates
• Installations requiring multiple burner rows in a single duct to increase total input capacity
• Retrofit and new installations in air ducts with space or emissions constraints

Models / Configurations

• Linnox Straight ULE – Single straight burner section for installation across the full width of a process air duct; available in standard lengths up to 9 ft (2,700 mm) with longer engineered lengths available
• Linnox Tee ULE – Double-T or cross-section geometry providing multiple rows of burner modules in a single duct; scales total burner input up to 45 MM Btu/h for high-capacity applications

Linnox ULE Accessories

• Eclipse Ratio Regulator – Eclipse-supplied ratio regulator required for all Linnox ULE installations; controls gas/air ratio across the full turndown range
• UV Scanner – Required flame detection device for all Linnox ULE configurations; flame rod detection is not available for this burner series
• Control Motor / Actuator – Modulates the air butterfly valve; must meet Linnox specifications: ≤2 rpm rotation, ≥25 in-lb torque, 90° stroke, continuous or high/low modulating, reversible
• Mounting Plate Assembly – For installation into insulated or non-insulated process air ducts
• Direct Spark Igniter Assembly – Ignitor rod assembly for Linnox burners (refer to spare parts documentation for specific part numbers)

Documentation