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Home » Error Code EP in an Air Conditioner: Causes and Solutions

Error Code EP in an Air Conditioner: Causes and Solutions

The EP error code in an air conditioner indicates a failure in the temperature switch located at the top of the compressor. It is important to remember that the highest temperature in the refrigeration cycle is found at the compressor outlet, just after the refrigerant gas is compressed. For this reason, the switch is located on top of the crankcase, very close to the refrigerant outlet.

Excessively high temperatures in the compressor can reduce the viscosity of the oil, affecting the proper lubrication of the compressor and gradually damaging its mechanical components. The EP error code can have several causes, and its diagnosis requires a detailed inspection. Below are some common causes and their corresponding solutions:


Causes and Solutions for the EP Error Code

1. Loose Connection

  • Cause: This is one of the most common reasons for the ÉPÉ error code.
  • Solution: Check that the temperature switch wires are properly inserted into the connector on the power board of the outdoor unit. If the wires are loose, reinsert them correctly.

2. Missing Switch on the Compressor

  • Cause: If the EP code appears after a repair, the switch might not have been installed.
  • Solution: Create a short-circuit bridge, but keep in mind that the unit will lack the high-temperature protection system.

3. High Temperature Recorded by the Switch

If the temperature recorded is excessively high and accompanied by a bad odor, consider the following options to resolve the problem:

A. Check the U, V, and W Compressor Wires

  • Verify the position of the wires and compare it with the instructions in the installation manual or the identification letters or colors.
  • If the sequence is incorrect, reconnect the wires in the correct order.

B. Check the System Pressure

  • Use a pressure gauge to measure the system pressure. For units with R32 or R410A refrigerant and with the unit running, the pressure should be approximately 120 PSI.
  • Remember that lower-than-normal power consumption may indicate a lack of refrigerant. Adjust the refrigerant charge to ensure the pressure is correct.

C. Inspect the Outdoor Ventilation

  • Ensure there are no obstructions preventing the air conditioner from dissipating heat properly.
  • Install the outdoor unit in the position indicated in the instruction manual and verify that the air intakes and outlets are free of blockages.

4. EP Code with No Other Apparent Problems

  • Cause: If the EP code appears but the compressor temperature is normal and there are no wiring issues.
  • Solution A: Create a short circuit in the high-temperature switch to bypass its operation. If the problem is resolved, replace the crankcase temperature switch.
  • Solution B: If the problem persists after replacing the switch, proceed with replacing the outdoor unit’s power board.

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