Lennox SL22KLV Heat Pump Error Code 109: Faulty Contactor Detected

Your Lennox heat pump model SL22KLV is displaying error code 109, indicating a faulty contactor that prevents the compressor and outdoor fan motor from operating continuously. You’ll need to identify the faulty component, take voltage readings, and diagnose the issue.

By understanding the error code, electrical loads, and operation, you can troubleshoot the faulty contactor and other possible causes. Now, take the next step to resolve the issue.

Understanding the Error Code

When your Lennox SL22KLV heat pump displays error code 109, it’s vital to understand what this code indicates.

The error code 109 is a clear indication of a faulty contactor, which is responsible for powering the compressor and outdoor fan motor in the outdoor unit. This faulty contactor prevents the compressor and outdoor fan motor from operating, resulting in the error code 109.

The contactor coil and normally open contacts are identified as potential faults, and the line voltage circuit may have a main power problem or the low-voltage circuit may have a faulty contactor or open pressure switch.

Also, Read: Lennox SL22KLV Heat Pump Error Code 108: Faulty Temperature Sensors (Indoor/Outdoor)

Electrical Loads and Operation

The electrical loads in your Lennox heat pump play a crucial role in its operation, and understanding their behavior is key to resolving the issue at hand.

As you investigate the faulty contactor error code 109, crucially examining the electrical loads’ impact on the heat pump’s operation is necessary.

• The indoor fan motor is running, but the outdoor fan and compressor aren’t running continuously.
• A clamp-on ammeter verifies the compressor is completely off.
• The outdoor fan’s lack of continuous operation indicates an electrical load issue.
• The compressor’s failure to run continuously is related to the faulty contactor.
• The faulty contactor prevents the compressor and outdoor fan from running continuously, resulting in error code 109.

Identifying the Faulty Contactor

You’ll need to consult the wiring diagram to pinpoint the faulty components, including the contactor coil and normally open contacts, that are causing the error code 109 on your Lennox Heat Pump Model SL22KLV.

Take a look at the contactor coil connections and make sure they’re receiving the proper voltage.

The contactor coil and normally open contacts are possible causes of the faulty contactor, along with the thermostat, high-pressure cutout, and low-pressure cutout.

Identify the faulty component and prepare for replacement.

Remember to replace the contactor with the power off to rectify the issue.

Also, Read: Lennox SL22KLV Heat Pump Error Code 107: Compressor Protection Mode Activated

Voltage Readings and Diagnosis

When diagnosing a faulty contactor error code, you’ll need to take specific voltage readings to identify the root cause.

You’ll want to check the contactor coil voltage, ensuring you’re getting 24 volts to verify the thermostat and pressure switches are closed.

Next, you’ll need to perform a line voltage check and contact closure test to rule out other potential causes.

Contactor Coil Voltage

Measuring contactor coil voltage is a crucial step in diagnosing issues with your Lennox heat pump.

As the first step in troubleshooting, you’ll want to check the voltage reading at the contactor coil connections.

• 24 volts should be measured at the connections to indicate that the thermostat and pressure switches are closed.
• A faulty contactor coil will prevent the contacts from closing, resulting in the compressor and outdoor fan motor not receiving power.

If the contacts aren’t closing, the coil is likely open and needs replacement, which can be verified by measuring the voltage at the contactor coil connections.

The contactor coil voltage reading can help identify if the issue is with the low-voltage circuit, which may have a faulty contactor or open pressure switch.

– A voltage reading of 240 volts at the contactor from the disconnect indicates that the line voltage circuit is functioning properly.

Line Voltage Check

With the contactor coil voltage measurement out of the way, you’re now ready to investigate the line voltage circuit.

Measure the voltage at the contactor from the disconnect; it should read 240 volts. If you don’t get 240 volts, you’re likely dealing with a power problem in the line voltage circuit, possibly due to a voltage drop, power outage, or electrical surge.

This issue could be preventing the contactor from functioning properly. A correct voltage reading will help you determine if the problem lies in the line voltage circuit or the low-voltage circuit. By isolating the faulty contactor error code 109 in your Lennox heat pump model SL22KLV.

Contact Closure Test

Since the line voltage circuit appears to be functioning correctly, you can now focus on the contactor’s electrical connections.

The contact closure test is a vital step in diagnosing the faulty contactor. This test helps you identify issues with the relay functionality and contact timing.

• Measure the voltage across the contactor coil terminals to verify the correct voltage is present during the contactor’s operating cycle.
• Use a multimeter to confirm the contactor coil is within the manufacturer’s recommended range.
• Check the contactor’s electrical connections for signs of wear, corrosion, or loose connections.
• Verify the contactor’s operating cycle timing is within the recommended specifications.
• Consult the Lennox heat pump’s wiring diagram to confirm correct wiring and connections.

Also, Read: Lennox SL22KLV Heat Pump Error Code 106: Defrost Sensor Failure Detected

Troubleshooting Other Possible Causes

You’ll need to check its settings to rule out any issues with the thermostat could be causing the error code.

Next, investigate low-voltage circuit issues, such as a faulty contactor or pressure switch, which might be triggering the error.

Additionally, main power problems with the line voltage circuit should be considered as a possible cause.

Thermostat Settings Check

Your Lennox heat pump isn’t producing the desired results, and it’s time to explore into the settings to identify potential issues.

You might be experiencing thermostat calibration errors, which can cause temperature fluctuations.

Check your thermostat settings to confirm they align with your cooling expectations.

• Check the temperature setting to confirm it’s not set too high or low, causing the heat pump to malfunction.
• Verify the thermostat mode is set to either “heat” or “cool” mode, depending on your current needs.
• Certify the thermostat is receiving power and functioning correctly.
• Check for any signs of physical damage or wear and tear on the thermostat or its components.
• Review your thermostat’s user manual to certify you’re using it correctly and following the recommended settings.

Low-Voltage Circuit Issues

Faulty low-voltage circuits can severely impede your Lennox heat pump’s performance, and it’s crucial to examine this aspect of the system.

If you’re experiencing error code 109, it’s possible that the low-voltage circuit is at fault. To troubleshoot, you’ll need to perform circuit analysis, voltage monitoring, and wire inspection.

Consult the wiring diagram to identify which components could be at fault in the low-voltage circuit, such as the thermostat, high-pressure cutout, and low-pressure cutout.

Verify the issue by measuring voltage readings, specifically 24 volts at the contactor coil connections, to identify the faulty component.

If the contactor coil is open, it needs replacement, ensuring the power is off to avoid electrical shock or further damage.

Main Power Problems

Main Power Problems (Troubleshooting Other Possible Causes) arise when low-voltage circuit issues, like error code 109, have been ruled out.

Now, you need to investigate other potential issues affecting your Lennox heat pump’s performance.

• Power fluctuations can cause the contactor to malfunction, leading to error code 109.
• Electrical surges can damage the contactor or other electrical components, resulting in the error code.
• Circuit overloads can prevent the heat pump from functioning correctly.
• Faulty wiring or connections can also cause power issues, leading to the error code.
• In some cases, a faulty main power supply can be the root cause of the problem.

Also, Read: Lennox SL22KLV Heat Pump Error Code 105: Low Pressure Detected in Outdoor Unit

Repair and Replacement Procedure

To guarantee a safe and successful repair, you must switch off the power supply before replacing the contactor, as even a momentary lapse in safety protocols can have serious consequences.

This System Overview highlights the importance of proper contactor replacement.

In your Repair Overview, verify the new contactor is identical to the faulty one to maintain proper system operation.

After replacement, you’ll need to re-establish power and observe one full cycle of operation.

Don’t forget to check and replace the indoor air filter if it’s dirty to achieve peak system performance.

Verifying the Repair

You’ve replaced the contactor and are ready to verify that the issue is resolved.

Now it’s time to confirm the system operates correctly and the error code is cleared.

To do this:

• Re-establish power to observe one full cycle of operation
• Verify warm air is coming through the vents to confirm the problem is solved
• Replace the indoor air filter if it’s dirty as part of the verification process
• Double-check that the contactor was replaced with the power off for safe and proper repair
• Perform a thorough system check to confirm the faulty contactor was the only issue and not a symptom of a larger problem.

Also, Read: Lennox SL22KLV Heat Pump Error 104: High Pressure Detected in Outdoor Unit

Final Verification and System Check

As you complete the verification process, now it’s crucial to conduct a final verification and system check to guarantee the Lennox Heat Pump Model SL22KLV issue. Re-establish power and observe one full cycle of operation to confirm the system is working correctly. Verify that warm air is coming through the registers to confirm the repair is successful.

Also, Read: Lennox SL22KLV Heat Pump Error Code102: Low Refrigerant Charge Detected

Frequently Asked Questions

Why Is My Contactor Not Pulling in My Heat Pump?

You’re wondering why your contactor isn’t pulling in; it’s likely due to a contactor voltage drop, overheating, or mechanical failure, causing the normally open contacts to remain open, preventing the compressor and fan motor from functioning properly.

How Do I Clear My Lennox Error Code?

“Clearing the error code is like hitting the reset button on your life – it’s a fresh start. You’ll need to follow resetting procedures, perform error diagnosis, and isolate the fault to get your system up and running smoothly again.

How Do You Read Lennox Error Codes?

You read Lennox error codes by consulting the error code manual or troubleshooting guide, which break down each digit’s meaning, or by contacting technical support to decode the issue and provide a solution.

Why Is My Heat Pump Not Reaching the Set Temperature?

You’re wondering why your heat pump isn’t reaching the set temperature. In cold weather, thermostat malfunction or faulty wiring can prevent the system from functioning correctly, resulting in inconsistent temperatures and inefficient heating.

Conclusion

You’ve pinpointed the root of the problem – error code 109 on your Lennox SL22KLV heat pump model. Now, it’s time to wrap up the repair. Think of it like piecing together a puzzle – you’ve identified the faulty contactor, diagnosed the issue, and replaced the faulty part. Double-check your work to confirm a seamless system operation.

With the repair verified, your heat pump should be humming along smoothly, like a well-oiled machine.