Honeywell L4064B2210 Fan and Limit Controller User Manual

1. Introduction

This manual provides instructions for the installation, operation, and maintenance of the Honeywell L4064B2210 Fan and Limit Controller. This device is designed to control the fan and limit functions in heating systems, ensuring safe and efficient operation.

2. Safety Information

WARNING: Electrical Shock Hazard. Can cause serious injury or death.

• Always disconnect power to the heating system before installing or servicing this control.
• Installation and servicing must be performed by a qualified heating technician.
• Ensure all wiring connections are secure and comply with local electrical codes.
• Do not operate the heating system if any part of the control is damaged.

WARNING: Burn Hazard. Can cause serious injury.

• The furnace and its components can become very hot. Allow components to cool before handling.

3. Product Overview

The Honeywell L4064B2210 is a combination fan and limit controller for furnaces. It features adjustable fan ON and OFF settings, as well as a high limit stop to prevent overheating. The control includes an 11 1/2 inch insertion probe for accurate temperature sensing within the furnace plenum.

Figure 1: Honeywell L4064B2210 Fan and Limit Controller. This image shows the front view of the controller with its adjustment dials and the temperature probe extending from the back.

4. Installation

Follow these steps for proper installation of the L4064B2210 Fan and Limit Controller:

1. Disconnect Power: Turn off all power to the furnace at the main service panel before beginning installation.
2. Remove Old Control: Carefully remove the existing fan and limit control. Note the wiring connections and temperature settings of the old unit for reference.
3. Prepare Wiring: Transfer wiring from the old control to the new L4064B2210, ensuring each wire is connected to the corresponding terminal. Refer to the wiring diagram provided with the product packaging. Some installations may require cutting a jumper wire; consult the specific wiring diagram for your furnace model.
4. Insert Probe: Insert the temperature sensing probe of the new control into the furnace plenum opening. Ensure the probe is fully inserted and positioned correctly to sense plenum air temperature.
5. Secure Control: Mount the L4064B2210 securely to the furnace using the provided mounting hardware.
6. Restore Power: Once installation is complete and all connections are secure, restore power to the furnace.
7. Test Operation: Initiate a heating cycle and observe the fan and limit control's operation to ensure it functions correctly.

5. Operating Instructions

The L4064B2210 features three adjustable settings:

• Fan ON Setting: This dial controls the temperature at which the furnace fan turns on to distribute heat. The factory setting is typically 125°F.
• Fan OFF Setting: This dial controls the temperature at which the furnace fan turns off after the heating cycle. The factory setting is typically 100°F.
• High Limit Stop: This dial sets the maximum temperature the furnace plenum is allowed to reach before the burner is shut off for safety. The factory setting is typically 200°F.

To adjust these settings, carefully rotate the respective dials to the desired temperature. It is recommended to set the fan ON/OFF temperatures according to your furnace manufacturer's specifications or to match the settings of your previous control for optimal comfort and efficiency. The high limit stop should generally not be adjusted from its factory setting unless advised by a qualified technician.

6. Maintenance

The Honeywell L4064B2210 Fan and Limit Controller is designed for reliable operation with minimal maintenance. However, periodic inspection is recommended:

• Annual Inspection: During routine furnace maintenance, have a qualified technician inspect the control for any signs of wear, damage, or loose connections.
• Probe Cleanliness: Ensure the temperature sensing probe is free from dust or debris that could affect its accuracy.
• Functionality Check: Verify that the fan turns on and off at the set temperatures and that the high limit safety function operates correctly.

7. Troubleshooting

If you experience issues with your heating system, consider the following troubleshooting steps:

• Fan Not Turning On:
  • Check if the furnace is receiving power.
  • Verify the fan ON setting is appropriate and the plenum temperature has reached it.
  • Inspect wiring connections for looseness or corrosion.
• Fan Not Turning Off:
  • Ensure the fan OFF setting is appropriate and the plenum temperature has dropped below it.
  • Check for continuous heat input that prevents the plenum from cooling.
• Furnace Overheating (High Limit Trip):
  • Check for restricted airflow (e.g., dirty air filter, blocked vents).
  • Verify the high limit setting is not set too low.
  • Ensure the fan is operating correctly to dissipate heat.

If these steps do not resolve the issue, contact a qualified HVAC technician for further diagnosis and repair.

8. Specifications

9. Warranty and Support

The Honeywell L4064B2210 Fan and Limit Controller is a genuine OEM replacement part. It is covered by Honeywell's standard manufacturer's warranty for original equipment manufacturer parts. For specific warranty details or technical support, please refer to the documentation included with your purchase or contact Honeywell customer service directly.