How to Clear P5 Error Code on a Mini-Split: A Comprehensive DIY Guide


The P5 error code on a mini-split air conditioning system is a common issue that indicates a problem with the water protection system, specifically the float switch in the condensate pan. This comprehensive guide will walk you through the step-by-step process of diagnosing and resolving the P5 error code, providing advanced hands-on details and technical specifications to help you tackle the problem as a DIY user.

Checking the Condensate Drain and Pump

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The first step in clearing a P5 error code is to inspect the condensate drain and pump. Ensure that the condensate drain is not clogged, as this can cause the condensate pan to overflow and trigger the P5 error. To check the drain:

  1. Locate the condensate drain line, which is typically a small PVC or plastic pipe that runs from the indoor unit to the outside or a drain.
  2. Visually inspect the drain line for any blockages, such as debris, dirt, or algae buildup.
  3. Use a wet/dry shop vacuum to suction out any debris or blockages in the drain line.
  4. Flush the drain line with clean water to ensure it is fully cleared.

Next, inspect the condensate pump (if your system has one). The condensate pump is responsible for removing the accumulated water from the condensate pan and pumping it outside. If the pump is not functioning correctly, it can also trigger the P5 error code. To check the condensate pump:

  1. Locate the condensate pump, which is typically installed near the indoor unit.
  2. Visually inspect the pump for any signs of damage, such as cracks, leaks, or debris buildup.
  3. Unplug the pump and test it by manually moving the float switch up and down. The pump should turn on and off in response to the float switch movement.
  4. If the pump is not functioning, it may need to be replaced.

Inspecting the Float Switch

The float switch is a critical component in the water protection system of a mini-split. It is designed to trigger the P5 error code when the condensate pan is full, preventing water damage to the unit. To inspect the float switch:

  1. Locate the float switch, which is typically located in the condensate pan of the indoor unit.
  2. Visually inspect the float switch for any signs of damage, such as cracks, corrosion, or debris buildup.
  3. Manually move the float switch up and down to ensure it is moving freely and triggering the switch.
  4. If the float switch is stuck or damaged, it will need to be replaced.

Checking the Wiring

The next step is to inspect the wiring of the float switch and the control board. Ensure that the wiring is secure and not damaged, as any issues with the wiring can also trigger the P5 error code. To check the wiring:

  1. Locate the wiring connections for the float switch and the control board.
  2. Visually inspect the wiring for any signs of damage, such as fraying, cuts, or water damage.
  3. Use a multimeter to test the continuity of the wiring, ensuring that there are no breaks or shorts.
  4. If the wiring is damaged, it will need to be repaired or replaced.

Resetting the Unit

If the issue is not immediately apparent, try resetting the unit. This can help clear any temporary glitches or issues that may be causing the P5 error code. To reset the unit:

  1. Locate the circuit breaker that supplies power to the mini-split system.
  2. Turn off the circuit breaker and leave it off for 4 consecutive hours.
  3. After 4 hours, turn the circuit breaker back on to restore power to the system.

Testing the Unit

After completing the above steps, test the unit to see if the P5 error code has been cleared. Turn on the system and monitor it for any signs of the error code reappearing. If the error code persists, it may be necessary to call a professional HVAC technician to diagnose and repair the issue further.

Conflict Mode Considerations

It’s worth noting that the P5 error code may also indicate a conflict mode, where one indoor unit is calling for cooling, and the other is calling for heating mode simultaneously. In this case, setting all indoor units to cooling mode and running them together for a short period may resolve the issue.

Technical Specifications and Advanced Details

To provide a more comprehensive guide, here are some additional technical specifications and advanced details for each step:

Condensate Drain and Pump

  • Condensate Drain Line Diameter: The typical condensate drain line diameter for a mini-split system is 3/4 inch (19 mm) PVC or plastic pipe.
  • Condensate Pump Specifications: The condensate pump should be rated for the specific mini-split system and have a lift capacity of at least 15-20 feet (4.6-6.1 meters) to ensure proper drainage.
  • Condensate Pump Power: The condensate pump typically operates on 120V AC power and should be connected to the same circuit as the indoor unit.

Float Switch

  • Float Switch Type: The float switch used in mini-split systems is typically a normally open (NO) type, which closes the circuit when the condensate level rises and the float is lifted.
  • Float Switch Voltage: The float switch operates on a low voltage, typically 24V AC, provided by the control board.
  • Float Switch Placement: The float switch is positioned in the condensate pan, with the float mechanism free to move up and down as the water level changes.


  • Wiring Connections: The float switch is connected to the control board using low-voltage wiring, typically 18-22 AWG (0.82-0.33 mm²) in size.
  • Wiring Insulation: The wiring should have a durable, moisture-resistant insulation to prevent short circuits or ground faults.
  • Wiring Routing: The wiring should be routed away from any potential sources of water or moisture to avoid corrosion or electrical issues.

Resetting the Unit

  • Capacitor Discharge Time: Unplugging the breaker for 4 consecutive hours allows the system’s capacitors to fully discharge, resetting the control board and clearing any temporary glitches.
  • Electrical Safety: Always exercise caution when working with electrical systems and follow proper safety protocols, such as turning off the power at the circuit breaker before performing any work.

By following this comprehensive guide and incorporating the advanced technical details, you’ll be well-equipped to diagnose and resolve the P5 error code on your mini-split system as a DIY user. Remember to always prioritize safety and consider calling a professional HVAC technician if the issue persists or you’re unsure about any of the steps.


  1. JustAnswer: My outside mini split has a p5 and p3 code popping up
  2. YouTube: Tech Tips: How to Resolve a P4 or P5 Error Code (L)
  3. Senville: P5 Error Code – Conflict Mode