Honeywell, L4006H1004/U, High Limit Aquastat, Manual Reset

Honeywell L4006H1004 Aquastat Controller – High Limit Strap-On Temperature Control

The Honeywell L4006H1004 is a strap-on high limit aquastat controller designed for regulating liquid temperature in hydronic heating systems. This model is commonly used to activate or interrupt electrical circuits based on fluid temperature, protecting equipment from over-temperature conditions. It features SPDT snap-action switching and an adjustable dial for precise setpoint selection.

Compatible with both horizontal and vertical pipe installations, the L4006H1004 is well suited for retrofit applications or systems that require temperature limit control without immersion wells. The unit includes a strap-on mounting clamp and features a visible scale for quick field adjustment.

Functional Features

• Control Type: High limit temperature controller
• Switch Type: SPDT snap-acting switch
• Setpoint Range: 100°F to 240°F
• Differential: Fixed
• Mounting: Strap-on, suitable for vertical or horizontal pipe

Electrical Ratings

• Voltage Range: 120 to 240 VAC
• Full Load Amperage: 5.1 A at 240 VAC
• Locked Rotor Amperage: Up to 48 A
• Control Action: Opens on temperature rise at setpoint

Mechanical Specifications

• Sensing Element: 3/8" x 2-7/8" copper bulb with capillary
• Mounting Hardware: Included pipe clamp for strap-on installation
• Scale: Dial with visible graduated markings
• Application: Boilers, storage tanks, and hydronic piping systems

Installation Notes

The L4006H1004 is intended for use by trained personnel familiar with electrical control systems. Ensure the controller is properly secured to the pipe and that the sensing bulb maintains direct contact for accurate temperature reading. All wiring should comply with NEC and local codes. Do not mount on insulated piping unless insulation is removed beneath the sensing bulb.

Contractor Notes

This unit is frequently used in high limit temperature applications where immersion wells are not available or where surface mounting is preferred. It is compatible with a wide range of circulating systems, especially in retrofit hydronic configurations where existing piping does not allow for well insertion.