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

When your Lennox Heat Pump Model Num SL22KLV displays error code 105, it indicates a low-pressure issue within the outdoor unit, often triggered by communication breakdowns between the outdoor unit and thermostat.

You’ll want to check the wiring connections, inspect the vent system, and verify a stable Wi-Fi connection. If the issue persists, it may be worth exploring further to identify the root cause and take preventative measures to avoid future error codes.

Understanding the Error Code 105

When your Lennox heat pump model SL22KLV displays error code 105, it’s indicating a communication breakdown between the outdoor unit and the thermostat.

This error code often points to a low-pressure switch malfunction, which can be caused by various factors. A technician will inspect the vent system to verify it’s clear and functioning properly.

They’ll also check the wiring connections between the outdoor unit and the thermostat to confirm they’re secure and not damaged, as faulty wiring can cause the communication error.

If the issue isn’t resolved, the technician may need to reset it by putting it in test mode or resetting low-voltage power to clear the error code and get your HVAC solutions up and running smoothly again.

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

Causes of Low Pressure in the Outdoor Unit

When troubleshooting the Lennox SL22KLV heat pump’s outdoor unit, you’ll want to investigate potential causes of low pressure, including refrigerant leaks that allow the refrigerant to escape, clogged coils that restrict airflow, and a faulty pressure sensor that provides incorrect readings.

Any of these issues can trigger error code 105 and shut down the heat pump. This is crucial to address these causes promptly to prevent further complications.

Refrigerant Leaks

Corrosion, damaged connections, or faulty installation can cause refrigerant leaks, leading to low pressure in the outdoor unit.

This can trigger error code 105 on your Lennox heat pump, resulting in system malfunctions. The low-pressure switch in the outdoor unit detects refrigerant leaks, shutting down the system to prevent damage and safety hazards.

If you notice reduced cooling or heating performance, or higher energy bills, prompt attention is vital to address the issue.

A professional HVAC technician should inspect and recharge the system, as improper handling can be hazardous to the environment and human health.

Don’t risk further damage – call an HVAC expert to diagnose and recharge your system.

Clogged Coils

One common culprit behind error code 105 on your Lennox heat pump is a clogged coil in the outdoor unit.

Dirty or clogged coils can increase pressure drops, reducing airflow and causing the low-pressure switch to trip, resulting in the error code.

In a Lennox heat pump, a clogged coil can also cause the compressor to work harder, leading to increased energy consumption and further system damage.

Cleaning or replacing the clogged coil can resolve the low-pressure issue and eliminate the error code, restoring normal heat pump operation.

If left unaddressed, clogged coils can lead to further damage, such as compressor failure, resulting in costly repairs or even replacement of your Lennox iComfort heat pump.

Faulty Pressure Sensor

As you troubleshoot error code 105 on your Lennox heat pump, another critical component to inspect is the pressure sensor in the outdoor unit’s control board.

This sensor monitors refrigerant pressure, and a malfunction can cause the system to shut down as a safety precaution, resulting in low pressure and error code 105.

Dirt, dust, or moisture accumulation can cause the pressure sensor to malfunction, triggering the low-pressure switch and shutting down the system.

Cleaning the pressure sensor or replacing it if damaged can resolve the issue.

To guarantee accurate refrigerant pressure readings and avoid further malfunctions, inspect the pressure sensor.

Also, Read: Lennox SL22KLV Heat Pump Error Code 103: Outdoor Unit Overcurrent Detected

Troubleshooting Steps for Error Code 105

You’ll need to take three key steps to troubleshoot error code 105 on your Lennox heat pump:

Resetting the thermostat, checking the Wi-Fi connection, and inspecting the outdoor unit will help you identify whether the issue lies with the thermostat’s communication, the outdoor unit’s low-pressure switch, or the Wi-Fi connection.

Resetting the Thermostat

The thermostat reset is a crucial step in troubleshooting the Lennox heat pump’s code 105 error, which indicates an Outdoor Unit Low Pressure issue.

You can try resetting the breaker, which may solve the issue by turning the circuit breakers off and on, potentially resolving the communication error. If the wet switch turns from red to green after the breaker reset, it may be a temporary issue that has been resolved.

However, if the thermostat still displays a communication error, further troubleshooting steps are necessary. If resetting the breaker doesn’t work, you may need professional assistance from an HVAC technician, such as airheatman, who specializes in heat pump issues and can provide further troubleshooting steps and assistance.

Checking Wi-Fi Connection

After ruling out issues with the thermostat and breaker, your attention turns to the Wi-Fi connection, a potential culprit in the error code 105 saga.

Check the router’s signal strength and distance from the outdoor unit to confirm a stable connection. A weak signal can cause communication problems, leading to error code 105.

If you’ve recently adjusted thermostat settings or installed a new Temperature Sensor, it may be interfering with the Wi-Fi connection. If the issue persists, you may need professional assistance from an HVAC technician, such as airheatman, who specializes in furnace, A/C, and heat pump issues.

They can diagnose and repair faulty outdoor unit components, like the low-pressure switch, to resolve the error code 105.

Outdoor Unit Inspection

To pinpoint the root cause of error code 105, inspect the outdoor unit, focusing on its low-pressure switch, which can become stuck open, thereby increasing the error count.

Check the outdoor unit’s low-pressure switch to verify it’s functioning correctly and not stuck open, which can cause the error count to increase.

The technician can reset the outdoor unit by putting it in test mode or resetting low-voltage power to clear the error code.

• Check the vent and combustion air inducer to locate any blockage that may be causing the error, and watch the high-pressure switch to determine how it functions during a heating cycle.
• Measure the pressure while it attempts to close during a heating cycle, and check the connections of the outdoor unit to rule out any electrical problems contributing to the communication issue.

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

Inspecting Vent Pipes and Filters

You’ll want to start by inspecting the vent pipes for any blockages or kinks that could be restricting airflow, which can trigger the low-pressure switch failure on your Lennox heat pump model SL22KLV.

Check the vent filter for cleanliness and replace it if necessary to resolve the low-pressure switch failure indicated by error code 105.

Verify that the vent pipes are securely connected to the outdoor unit and not damaged to prevent low-pressure switch failures.

Guarantee the vent pipes aren’t clogged with debris or ice to maintain proper system operation.

Inspect the vent pipes for signs of moisture or water damage to identify potential causes of low-pressure switch failures.

Resetting the Outdoor Unit

The outdoor unit’s reset is a crucial step in resolving error code 105 on your Lennox heat pump model SL22KLV.

This error code indicates a communication error between the outdoor unit and the indoor unit.

• To reset the outdoor unit, a technician will put the unit in test mode or reset the low-voltage power to clear error code 105.
• The technician will check the system using several methods to determine the cause of the issue and reset the outdoor unit.
• Error code 105 when the outdoor unit’s low-pressure switch malfunctions five times or more during one heating or cooling cycle.
• Once the issue is fixed, and the outdoor unit is reset successfully, the error code should automatically clear.

Also, Read: Lennox SL22KLV Heat Pump Error Code 101: Loss of Communication Between Outdoor and Indoor Units

Professional Assistance for Persistent Issues

If error code 105 persists after resetting the outdoor unit, you’re likely dealing with a more complex issue that requires expert guidance. In the HVAC industry, expert assistance is vital in resolving persistent issues like Outdoor Unit Low Pressure**. You’ve been connected with a verified expert, airheatman, who specializes in furnace, A/C, and heat pump issues. With 51 years of experience, airheatman provides troubleshooting steps and offers further assistance if needed.

Preventing Future Error Codes

Regular maintenance is key to preventing Lennox heat pump issues.

By staying on top of your system’s needs, you can avoid costly repairs and minimize downtime.

To prevent future error codes like the 105 error indicating low pressure in the outdoor unit, follow these tips:

• Schedule regular system or servicing appointments with a trusted conditioning Co to confirm your Lennox Heat Pump is running efficiently.
• Keep an eye on your system’s air filters, and replace them regularly to prevent dust buildup that can lead to error messages.
• Certify proper installation and maintenance of your outdoor unit to prevent low pressure issues.
• Consider investing in a tech support package for your Lennox Heat Pump to receive priority support and supply lasting HVAC solutions.

Also, Read: Lennox XP25 Heat Pump Error Code 471: Dual-Fuel Control System Error

Frequently Asked Questions

What Does Error Code 105 Mean on Lennox?

You’re seeing error code 105, which means your system’s low-pressure switch is triggering a communication error, likely due to low refrigerant, faulty compressor, defective valve, refrigerant leaks, low airflow, blocked condenser coils, or blocked air, requiring a malfunctioning sensor check.

How to Clear Lennox Error Code?

Did you know that 70% of HVAC issues are electrical? To clear Lennox error codes, follow troubleshooting steps: reset the system, check error code meanings, and identify faulty components using diagnostic tools to resolve outdoor unit issues like pressure sensor problems.

What Is the Code P0 on a Lennox Mini Split?

When you encounter the code P0 on your Lennox mini split operation is normal, but it’s vital to perform regular Mini split maintenance to guarantee prime Split system advantages and Split system design.

How Do You Reset a Lennox Heat Pump?

To reset your Lennox heat pump, you’ll first want to confirm you’re not experiencing pump failure symptoms, defrost cycle issues, or outdoor unit problems, then try tripping the circuit breaker to resolve thermostat connection troubles, refrigerant leak detection, or system power outages.

Conclusion

You’ve navigated the troubleshooting maze for your Lennox heat pump model SL22KLV, and now you’re equipped to tackle error code 105 like a pro. Think of your system as a finely-tuned orchestra: one missed note can throw everything off. By following these steps, you’ll be back in harmony in no time.