Aquastat Hi/Lo Limit Controller | Replaces Honeywell L6006A1145 | NBK-21048

NBK-21048 – Aquastat Hi/Lo Limit Controller | Replaces Honeywell L6006A1145

The NBK-21048 Aquastat Hi/Lo Limit Controller is a precision temperature control device engineered for outdoor wood boilers, hydronic heating systems, and hot water heating applications. With independently adjustable high- and low-temperature setpoints, it automatically protects your system from overheating and maintains safe, efficient operation — giving you reliable heat control season after season.

Key Features

• Dual Hi/Lo Setpoints – Independently adjustable high and low temperature thresholds for precise hydronic system control
• Automatic Safety Shutoff – Cuts burner or circulator operation the moment temperature limits are exceeded
• Adjustable Differential – Fine-tune cycle characteristics to reduce short-cycling and maximize system efficiency
• Versatile Compatibility – Suitable for outdoor wood boilers, hydronic baseboard, radiant floor, and hot water tank applications
• Direct OEM Replacement – Drop-in replacement for Honeywell L6006A1145 with no modifications required

Specifications

• SKU: NBK-21048
• Part Number: 21048-NBK
• Type: Aquastat Hi/Lo Limit Controller
• Application: Outdoor wood boilers, hydronic heating, radiant floor heating, hot water tanks

Replaces / Cross-Reference

• Honeywell: L6006A1145

Common Applications

• Outdoor wood boilers and biomass boilers
• Hydronic baseboard and radiant floor heating systems
• Hot water storage tanks requiring dependable high/low limit control
• Heating loops requiring reliable high-limit protection

Why Choose the NBK-21048?

When your heating system needs dependable temperature protection, the NBK-21048 delivers. Its dual-setpoint design and automatic shutoff safeguard your boiler and circulator from thermal damage, while the adjustable differential keeps your system running at peak efficiency. A trusted, cost-effective replacement for Honeywell L6006A1145.