NBK-20929-1 – Aquastat Well Clamp | Replaces Honeywell 121371AAThe NBK-20929-1 Aquastat Well Clamp is engineered to firmly secure aquastat sensor bulbs inside immersion wells in outdoor wood boilers, hydronic heating systems, and water heaters. A loose sensor bulb means inaccurate temperature readings, erratic cycling, and wasted energy — the NBK-20929-1 eliminates that problem with a positive-locking clamp that holds the bulb in firm thermal contact with the well at all times.Key FeaturesPositive-Locking Clamp Design – Holds aquastat sensor bulbs tightly in place for accurate, stable temperature readingsHeavy-Duty Construction – Resists vibration and loosening under continuous heating system operationEasy Installation – Simple clamp design fits common aquastat well sizes used in hydronic and boiler systemsDirect OEM Replacement – Drop-in replacement for Honeywell 121371AA with no modifications requiredBroad Compatibility – Works with most standard aquastat immersion wells in outdoor boiler and hydronic heating applicationsSpecificationsSKU: NBK-20929-1Part Number: 20929-1-NBKApplication: Secures aquastat sensor bulbs into immersion wells for stable temperature controlReplaces / Cross-ReferenceHoneywell: 121371AACommon ApplicationsOutdoor wood boilers and biomass boilersHydronic baseboard and radiant floor heating systemsResidential and commercial water heater installationsAny system using aquastat immersion wells requiring secure sensor attachmentWhy Choose the NBK-20929-1?When an aquastat sensor bulb shifts or rattles loose inside its well, your heating system loses the accurate temperature feedback it needs to operate efficiently. The NBK-20929-1 restores that precision with a durable, vibration-resistant clamp that keeps the sensor locked in optimal thermal contact — a direct, cost-effective replacement for Honeywell 121371AA.
