Honeywell, L6006C1018/U, High and Low Limit Aquastat, 5 to 30 deg F, 150 deg F

Honeywell L6006C1018 Aquastat Controller – High or Low Limit Temperature Control with Circulator Switching

The Honeywell L6006C1018 is a strap-on or immersion-type aquastat designed for high or low limit temperature control in hydronic heating systems. This model features SPDT switching action and includes an adjustable differential to allow for system flexibility in maintaining water temperature within set parameters.

It is suitable for use in both boiler and storage tank applications and can be mounted directly into a 1/2″ NPT well or strapped to the pipe using the included clamp. The L6006C1018 is commonly used to control circulator operation based on water temperature or to activate burner functions under limit control conditions.

Application Features

• Control Function: High or low limit controller with circulator switching capability
• Switch Type: SPDT (single-pole, double-throw)
• Differential Adjustment: 5°F to 30°F
• Temperature Range: 65°F to 200°F
• Mounting: Vertical immersion or surface-mount (strap-on) with clamp

Technical Specifications

• Voltage: 120/240 VAC
• Electrical Load: 5.1 A to 48 A resistive, based on system voltage and relay wiring
• Sensor Bulb Size: 3/8″ x 2-7/8″ copper
• Capillary Length: 5 ft
• Humidity Range: 0–95% RH (non-condensing)

Installation Requirements

The L6006C1018 should be installed by qualified technicians familiar with electrical controls and boiler operations. When used as an immersion controller, a 1/2″ NPT well is required. For strap-on applications, ensure firm contact between the sensing bulb and pipe surface using the provided mounting hardware. Setpoint and differential adjustments must be verified with a calibrated temperature reference during commissioning.

Contractor Notes

This controller is used in a wide range of heating system designs, particularly where separate circulator and burner control functions are desired based on water temperature. Its adjustable differential allows for fine-tuning of heat cycle timing and flow response, improving system stability and comfort. Suitable for hot water heating systems in both residential and light commercial applications.