E2
American Standard Low-Pressure Switch Open / Loss of Charge

Thermostat or control board shows E2 and cooling stops intermittently

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Low refrigerant charge due to leak, Restricted indoor evaporator airflow, Frozen evaporator coil, Faulty low-pressure switch on American Standard condensing unit

How to Fix / Troubleshooting

Safety first: Turn off power to both indoor and outdoor units before opening panels. Do not attempt to add refrigerant yourself.

  • Check air filter and airflow: Remove and inspect the return air filter in the American Standard air handler or furnace. Replace if dirty. Ensure all supply and return vents are open and not blocked by furniture or rugs.
  • Inspect evaporator coil for ice: Open the indoor unit access panel to view the evaporator coil. If you see ice buildup, turn the system off and set the thermostat fan to ON to thaw the coil for several hours. Do not chip ice off with tools.
  • After thawing: Restore normal settings and run the system. If E2 reappears or the suction line outside frosts over, there is likely a refrigerant issue or airflow restriction.
  • Professional leak check: A licensed technician should check the American Standard coil, line set, and service valves for leaks, repair them, and weigh in the correct R-410A charge. Operating with low charge can damage the compressor.
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Repair Difficulty

Hard 4/5

Required Part

Low-Pressure Switch
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