If your Lennox SL22KLV heat pump is displaying error code 122, indicating a high pressure switch open, it’s vital to address the issue promptly to prevent further damage or safety hazards. You’ll need to investigate the system charge, verifying the refrigerant level and comparing it to the nameplate specification.
Certify the outdoor coil is clear of debris, the air filter isn’t clogged, and the pressure switch isn’t faulty. Look deeper into the issue to resolve it effectively.
Important Point
Understanding High Pressure Lockout
When your heat pump’s high pressure lockout kicks in, it’s a crucial safety feature that shuts down the system to prevent overheating and potential system failure.
This feature is triggered by a high pressure switch that monitors the refrigerant pressure in the system. If the pressure exceeds the set limit, the switch shuts off the system to prevent damage.
The outdoor unit’s static pressure, discharge line, and air filter all play a role in maintaining proper refrigerant pressure. A pressure drop or blockage in these components can trigger the high pressure lockout.
Regular maintenance can help prevent this issue by ensuring the air filter is clean and the condenser coils are clear.
Also, Read: Lennox SL22KLV Heat Pump Error Code 121: Low Pressure Switch Open Detected
Causes of High Pressure Switch Open
Now that you’ve identified the high pressure lockout issue, it’s time to pinpoint the underlying reasons behind the high pressure switch open.
In a Lennox heat pump, the high pressure switch open is often caused by refrigerant overcharge or undercharge, which affects the system’s ability to operate in heat mode.
Another common cause is a faulty pressure switch, which can malfunction and trigger the high pressure lockout.
Additionally, a clogged or restricted airflow can also cause the pressure to rise, leading to the high pressure switch open error code.
As a service tech, you must conduct a thorough examination of the system and perform the necessary repairs to get it up and running efficiently again.
Error Code 122 Diagnosis
Error code 122 on a Lennox heat pump signals that the high-pressure switch is open, triggering a safety shutdown to prevent system damage from excessive pressure. To diagnose this issue, you’ll need to investigate the system charge.
| Step | Description | |
|---|---|---|
| 1 | Verify system charge | Check the system charge using various methods. |
| 2 | Weigh out current refrigerant charge | Compare it to the name plate specification. |
| 3 | Recharge refrigerant | Add refrigerant according to the chart on the back of the panel if necessary. |
| 4 | Clear error code | The error code should clear automatically once the issue is fixed. |
Also, Read: Lennox SL22KLV Heat Pump Error Code 120: Thermistor Failure Detected
Evaporator Coil and Pressure Switches
You’ve addressed the high-pressure switch issue, and now it’s necessary to inspect the evaporator coil and pressure switches.
As an HVAC Tech in commercial HVAC/R, you know that dirty coils can cause high pressure lockouts.
Check the outdoor coil for blockages or debris, ensuring proper airflow.
A high pressure lockout can occur if the pressure is faulty or stuck, causing the light to stay on.
Inspect the pressure switch for signs of wear or malfunction.
If the pressure switch lockout is triggered, it’ll prevent the heat pump from operating.
Verify that the pressure isn’t too high, which can activate the high pressure lockout.
Filter Driers and Refrigerant Flow
The filter drier, a crucial part of the refrigerant circuit, is responsible for removing moisture and debris that can cause compressor failures or refrigerant flow restrictions.
When the filter drier becomes clogged, refrigerant flow is restricted, leading to high pressure and eventual high pressure lockout.
- The pressure switch will open, resulting in an error code 122.
- Refrigerant flow restrictions can cause the heat pump to malfunction, leading to a pressure lockout HVAC issue that requires repair and service by an HVAC technician.
Also, Read: Lennox SL22KLV Heat Pump Error Code 119: Outdoor Airflow Restriction Detected (Blocked Coil/Fan)
Troubleshooting the Lennox Heat Pump
When your Lennox heat pump malfunctions, troubleshooting the issue efficiently is crucial to minimize downtime and prevent potential damage.
If you’re experiencing a high pressure switch open error (122), it’s necessary to identify the root cause.
Check your air filter – is it dirty or clogged? Restricted airflow can increase refrigerant pressure, triggering high pressure lockout.
Verify you’ve got the right amount of refrigerant, as improper levels can cause pressure to rise.
If you’re unsure or can’t resolve the issue, it’s necessary to bring in a professional.
They’ll inspect and service your heat pump system to prevent further damage.
Preventing High Pressure Lockout
Regular maintenance is your best defense against high pressure lockout, a common issue that can bring your Lennox heat pump to a grinding halt.
This lockout issue can trigger an error code, and the pressure switch may stay open, leading to a high pressure lockout; light stays on, indicating a problem.
To prevent high pressure lockout, follow these steps:
- Certify proper refrigerant levels and check for leaks
- Clean the outdoor coil regularly to prevent dirt buildup
- Inspect the compressor and fan motor for signs of wear or damage
Also, Read: Lennox SL22KLV Heat Pump Error Code 118: Indoor Airflow Restriction Detected (Clogged Filter/Blocked Duct)
Seeking Professional Assistance
If your Lennox heat pump error code persists, you’ll likely need expert help to diagnose the issue. A service technician will diagnose the problem, guaranteeing you don’t attempt to release refrigerant, which is against EPA rules and can lead to further complications.
| Step | Action |
|---|---|
| 1 | Check refrigerant charge and recharge if necessary. |
| 2 | Verify airflow across air handler and guarantee air filter is clean. |
| 3 | Check pressure switch and airflow; if good, system may be overcharged. |
| 4 | Reset outdoor unit by putting it in test mode or resetting low-voltage power to clear the error code. |
The technician will guarantee the refrigerant charge is correct, airflow is good, and the system is functioning properly to prevent high pressure lockout and clear the error code.
Also, Read: Lennox SL22KLV Heat Pump Error Code 117: Faulty Pressure Switch Detected
Frequently Asked Questions
How to Reset Lennox High Pressure Switch?
To reset your Lennox high pressure switch, consult the Lennox manual for guidance, then perform heat pump troubleshooting, and consider switch replacement or pressure sensor cleaning, before attempting system rebooting or high voltage testing.
Why Is My High Pressure Switch Failed Open?
You’re stuck with a failed open high pressure switch, and it’s like a ticking time bomb waiting to destroy your entire system! Faulty compressor, worn bearings, dirty coils, refrigerant leaks, or corrosion damage could be the culprits behind the malfunction.
How Do You Reset a High Pressure Switch on a Heat Pump?
You reset a high pressure switch on a heat pump by identifying underlying issues like system overload or pump failure, then perform pressure switch testing, sensor calibration, and pressure regulation to prevent fault detection and high pressure symptoms, ensuring proper heat pump maintenance and repair.
How to Fix a High Pressure Fault in a Heat Pump?
To fix a high pressure fault in your heat pump, you’ll need to identify and address the underlying issue, such as a pressure sensor issue, refrigerant leakage, or faulty compressor diagnosis, to prevent pump overheating and optimize system performance.
Conclusion
As you navigate the complex landscape of heat pump troubleshooting, remember that error code 122 is a warning sign, a beacon flashing ” danger” in the darkness of system failure. Heed its call, and you’ll avoid the treacherous terrain of costly repairs and prolonged downtime.
By mastering the intricacies of pressure switches and evaporator coils, you’ll emerge victorious, your Lennox heat pump humming in harmony, a badge of honor to your technical prowess.
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