Aquastat Hi/Lo Limit Controller | Replaces Honeywell L6006C1018/U | NBK-21189

NBK-21189 – Aquastat Hi/Lo Limit Controller  The NBK-21189 Aquastat Hi/Lo Limit Controller is designed to deliver precise temperature control for hydronic heating systems, outdoor wood boilers, and similar applications. It provides accurate high- and low-temperature cut-offs to prevent overheating and maintain safe, efficient operation. Key Features Hi/Lo Temperature Control – Dual setpoints regulate high and low temperature thresholds, ensuring consistent system performance Versatile Application – Suitable for outdoor wood boilers, hydronic heaters, and various heating system configurations Reliable Safety Shutoff – Automatically halts burner or circulator operation when temperature limits are exceeded Adjustable Differential – Allows fine-tuning of cycle characteristics for optimal system efficiency Specifications SKU: 21189 Category: Outdoor Boiler / Limit Controllers Type: Aquastat Hi/Lo Limit Controller Operating Range: Suitable for standard hot water heating systems Equivalent To Honeywell: L6006C1018/U Common Applications Outdoor wood boilers Hydronic baseboard and radiant heating systems Hot water heater tanks requiring dependable limit control Why Choose This Aquastat The NBK-21189 delivers dependable high- and low-limit protection to safeguard heating equipment. Its durable design ensures consistent operation and helps extend the life of boilers, circulators, and associated system components.