Honeywell L6191A2015U aquastat

Aquastat (thermostat) Honeywell L6191A2015U is a dual immersion thermostat combining two independent liquid-filled sensors in one housing: one for temperature control, the other for emergency protection (limit thermostat). This design allows simultaneous control of pump or burner operation and safe system shutdown in case of overheating. The device is installed directly into the heat exchanger well (immersion mounting) and is designed for water temperature control in boilers, indirect water heaters, and similar water heating equipment. Technical specifications Parameter Value Part numbers L6191A2015U, 534.109.020 Manufacturer Honeywell Mounting type Immersion Sensor type Liquid (two independent) Working medium Water Protection class IP40 Composition Dual aquastat (controller + limit) Key advantages Two sensors in one device: Combines the functions of a working controller and an emergency limit, simplifying installation and saving space on the control panel. Accurate liquid measurement: Highly sensitive liquid filling ensures fast response to temperature changes compared to bimetallic plates. Ease of adjustment: Two independently operating functional modules allow flexible configuration of system parameters. Reliable protection: The limit thermostat provides emergency shutdown of equipment when the permissible temperature is exceeded. Operating principle and application The aquastat is immersed in the heat exchanger well. The controller sensor maintains the set temperature by controlling the pump or fuel supply. The limit sensor acts as a safety device: in case of working circuit failure and overheating, it opens the contacts, stopping the boiler. This model is used in residential and commercial heating systems