How do I fix my Daikin Air Conditioner, model FTXM50QVMA, that has a U4 fault code?

Alton Alexander
By Alton AlexanderUpdated on June 4th, 2022

One of the error codes that can occur with a Daikin air conditioner is code U4. This code indicates that the air conditioner is not receiving the proper amount of power. This can happen for a variety of reasons, including a tripped circuit breaker or a blown fuse. If the problem is not corrected, the air conditioner will not be able to operate properly and may eventually stop working entirely.

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  • daikin code u4

1. Check the outdoor unit for proper operation

  1. Open the front cover of the outdoor unit.
  2. Check the air flow. The air flow should be sufficient to prevent the accumulation of dust and debris on the fan and motor.
  3. Check the motor and fan blades for proper operation.
  4. Check the power cord connection.
  5. Check the unit for proper operation.

2. Clean or replace the air filter

  1. Disconnect the power to the air conditioner.
  2. Open the front cover.
  3. Remove the air filter.
  4. Clean the air filter with a damp cloth.
  5. Replace the air filter.
  6. Replace the front cover.

3. Check the refrigerant level and add refrigerant if needed

  1. Check the refrigerant level. If necessary, add refrigerant.
  2. Check the refrigerant charge.
  3. Clear the error code.

4. Inspect the outdoor unit for debris or obstructions

  1. Look for any debris or obstructions in the outdoor unit. This could include leaves, twigs, rocks, or any other items that may have fallen onto the unit. If there are any obstructions, remove them using a vacuum cleaner or a broom.
  2. Check for any leaks. If there are any leaks, fix them by replacing the seals or the hose.
  3. Check for any damages. If there are any damages, fix them by replacing the parts that need to be replaced.

Still not working? maybe try one of these options:

  1. Check the outdoor unit coils for dirt or debris.
  2. Clean the outdoor unit coils.
  3. Check for proper operation of the condenser fan.
  4. Check for proper operation of the evaporator fan.
  5. Inspect the ductwork for leaks or blockages.
  6. Have a trained technician inspect and service the unit.