Honeywell L4069A-1060 Fan Limit Control Instruction Manual

1. Product Overview

The Honeywell L4069A-1060 is a fan limit control designed to provide high-temperature burner cutout, protecting warm air furnaces from overheating. This device utilizes a snap-acting switch actuated by a bimetallic element, which is inserted directly into the furnace plenum. It features an adjustable set point range and a fixed differential to ensure reliable temperature regulation.

Figure 1: Side view of the Honeywell L4069A-1060 Fan Limit Control unit, showing the bimetallic element and housing.

Key Features:

• Provides high-temperature burner cutout for safety.
• Protects various types of warm air furnaces from overheating.
• Actuated by a bimetallic element for direct plenum temperature sensing.
• Adjustable set point range for flexible application.

2. Specifications

Figure 2: Product packaging highlighting the adjustable range, insertion length, and operation mode.

3. Setup and Installation

Installation of the L4069A-1060 Fan Limit Control should be performed by a qualified technician. Ensure all power to the furnace is disconnected before beginning installation.

Mounting:

1. The bimetallic element must be inserted directly into the furnace plenum to accurately sense air temperature.
2. Ensure the element hole in the plenum is appropriately sized. If necessary, enlarge the existing hole or relocate the control to a suitable position.
3. If relocating the control, cover the old element and mounting holes. A new case and cover (part no. 132475E) may be required.

Wiring:

• The snap-acting switches feature push-in wiring terminals for positive and quick electrical connections.
• Refer to the furnace manufacturer's wiring diagrams for correct electrical connections.
• This control typically requires a separate fan control, such as a Honeywell L4068F Fan Control, for complete system operation.

Figure 3: Product box detailing functional replacements for various control models. Consult this information for compatibility during replacement.

Replacement Information:

The L4069A-1060 can serve as a functional replacement for several other limit controls. When replacing, pay close attention to the required settings and insertion length. Refer to the table below for common replacements:

4. Operating Instructions

The L4069A-1060 operates by opening its circuit when the plenum temperature rises to the set point, thereby cutting off the burner to prevent overheating. The control's adjustable range allows for customization within specified limits.

Setting the Temperature:

• The control has an adjustable set point range of 180°F to 250°F.
• The high limit stop is factory installed at 200°F, which is the maximum recommended operating temperature for many furnace applications.
• Adjust the set point according to the furnace manufacturer's recommendations and local codes.

Differential:

The L4069A-1060 has a fixed differential of 25°F (nominal). This means that once the control opens the circuit at the set point, it will not close the circuit again until the temperature drops approximately 25°F below the set point, ensuring stable operation and preventing rapid cycling.

5. Maintenance

The Honeywell L4069A-1060 Fan Limit Control is designed for reliable operation with minimal maintenance. However, periodic inspection by a qualified technician is recommended to ensure continued safe and efficient performance.

• Annual Inspection: Have the control and associated furnace components inspected annually by a qualified HVAC technician.
• Cleanliness: Ensure the bimetallic element and surrounding area in the plenum are free from dust, debris, or obstructions that could impede accurate temperature sensing.
• Wiring Integrity: Check for any signs of loose or damaged wiring connections during inspections.

Figure 4: Top view of the control unit, showing the housing and the insertion element extending from it.

6. Troubleshooting

If your furnace is experiencing issues related to overheating or improper fan operation, the L4069A-1060 Fan Limit Control may be a factor. Always consult a qualified HVAC technician for diagnosis and repair.

Common Issues and Potential Causes:

• Furnace Overheating:
  • Incorrect set point adjustment.
  • Faulty bimetallic element or switch.
  • Obstruction preventing proper air flow around the element.
• Burner Not Activating:
  • Control stuck in open circuit position.
  • Wiring issues or loose connections.
• Inconsistent Operation:
  • Dust or debris on the bimetallic element affecting temperature sensing.
  • Control nearing end of service life.

Warning: Do not attempt to repair or bypass the limit control. This is a safety device. Any malfunction requires professional diagnosis and replacement.

7. Warranty Information

Specific warranty details for the Honeywell L4069A-1060 Fan Limit Control are typically provided at the point of purchase or included with the product packaging. For comprehensive warranty terms and conditions, please refer to the documentation supplied with your device or contact Honeywell customer support directly.

8. Support

For technical assistance, product inquiries, or to locate authorized service providers, please contact Honeywell customer support. Contact information can typically be found on the official Honeywell website or on the product packaging.

Honeywell International Inc.
(Refer to official Honeywell website for current contact details and support resources.)