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Error code reference
LG Heat Pump Error Code P722
Compressor down by low pressure sensor protection control 2.
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What the P722 error code actually means
Your LG heat pump has shut itself off to protect the compressor because it detected unusually low pressure in the refrigerant system. This is a safety feature that prevents serious internal damage. The unit will not turn back on until a technician identifies and corrects the cause of the low pressure condition.
Diagnostic procedure
The full P722 procedure
Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.
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1
Confirm the fault
Power cycle the unit: switch off the breaker for 60 seconds, then restore power. If the code returns, the fault is persistent and the procedure below isolates the cause.
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Most common causes of P722
Ranked by how often they cause this code
- 1Low refrigerant charge due to a leak
- 2Blocked or restricted expansion valve
- 3Restricted or reduced airflow across the coil
- 4Faulty low pressure sensor
- 5Wiring fault in sensor circuit
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Questions people ask about P722
What does P722 mean on a LG heat_pump?
P722 indicates that the compressor has been shut down by a low pressure sensor protection control event, specifically protection control 2. The refrigerant circuit's suction-side pressure dropped below an acceptable threshold, triggering the system to stop the compressor to prevent mechanical damage. The unit will not restart until the cause of the low pressure condition is identified and corrected.
Is it safe to keep running my LG heat pump when P722 is displayed?
No. The P722 code causes the compressor to shut down as a protective measure, and the unit will not run normally while this fault is active. Attempting to repeatedly reset and restart the system without addressing the underlying low pressure condition could cause additional stress on components. Leave the system off and schedule a service call.
How much does it cost to repair a P722 error on an LG heat pump?
Repair costs vary significantly depending on the cause. A refrigerant leak search and recharge can range from roughly 200 to 600 dollars depending on the refrigerant type and amount needed. Replacing a faulty expansion valve or low pressure sensor may cost between 150 and 500 dollars including labor. If the compressor itself has sustained damage from running low on refrigerant, replacement costs can range from 800 to over 2000 dollars.
Can I fix the P722 error myself?
Some basic checks are within reach for a knowledgeable homeowner, such as inspecting and replacing air filters, clearing debris from around the outdoor unit, and checking that all supply and return vents are open. However, diagnosing refrigerant pressure levels, locating leaks, and recharging refrigerant require EPA Section 608 certification and professional equipment. It is recommended to contact a certified HVAC technician for a full diagnosis.
Will resetting the unit clear the P722 code?
A power reset may temporarily clear the code and allow the unit to attempt a restart, but if the root cause of the low pressure condition has not been corrected, the fault will return. Repeated occurrences of the P722 code, which is designated as protection control 2, suggest the problem is persistent rather than a one-time anomaly. A reset without repair is not a lasting solution.
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