Resideo L4008E1156 Aquastat Controller 130-270°F 66

The Resideo L4008E1156 is a high-limit manual reset aquastat controller for boiler and hydronic heating systems, using a remote bulb sensing element with a 66-inch capillary for immersion well mounting. It operates over a 130°F to 270°F range with an SPST-NC switch that breaks on temperature rise above setpoint, requiring manual reset once tripped. Rated for 240V line voltage service with a 5-30A contact rating, it mounts horizontally or vertically and includes heat-conductive compound for proper thermal transfer at the immersion well. This is a hardwired, non-programmable control intended for professional installation. It is commonly applied where boiler overheating, high-limit lockout, or burner cycling issues indicate a failing high-limit control. Installation requires an immersion well or thermowell, and use of the supplied heat-conductive compound is recommended to ensure accurate bulb temperature sensing.