Low pressure cutout: the low pressure switch tripped 3 times within the same thermostat call, so the compressor and outdoor fan are off.
Homeowner part this code names: thermostat.
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Goodman 01, also shown as L1, is a low-pressure cutout. The low pressure switch tripped 3 times during the same thermostat call, so the compressor and the outdoor fan are off. The outdoor display reads 01 or L1. Causes are an open low pressure switch, low refrigerant charge or a restriction, low indoor airflow, the thermostat setting, and a supply-voltage problem. The homeowner step is the thermostat setting and anything restricting indoor airflow. The manual says to verify indoor airflow, charge, and the thermostat setting. Charge is the technician half of that sentence. Technician steps are to read the switch resistance, read pressure on a gauge, and replace the switch only if the pressure is not low. If the pressure is low, verify airflow and charge, and check the voltage wires, involving the electric company if needed. This is not the high-side fault 02 / L2.
Likely causes
- Open low pressure switch
- Low refrigerant charge or a restriction
- Low indoor airflow
- Thermostat setting
- Supply voltage problem
Safe checks for 01 / L1
- Check the thermostat setting and look for anything restricting indoor airflow (the manual says to verify indoor airflow, charge and thermostat setting)
- Techniciancheck the resistance of the low pressure switch; read the pressure on a gauge and replace the switch if the pressure is not low
- Technicianif the pressure is low, verify indoor airflow and refrigerant charge, and check voltage wires (involve the electric company if needed)
Capacitors can hold a charge after the power is off. Safety terms.
When to call a pro
Call a licensed HVAC technician: low pressure lockouts involve refrigerant and pressure readings.
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Parts & tools for this fix
Taken from this code's causes or steps. A search link opens Amazon results and does not confirm a fit. Check the model number in the manual.
Thermostat: guide
In this code: Thermostat setting
Multimeter for appliance and HVAC diagnosis: guide
In this code: Supply voltage problem
This one is for a technician to test or replace, so we only explain it and do not link to buy it.
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