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<h2 id="introduction"><u>Introduction</u></h2><p>The &quot;P4&quot; error code indicates the outdoor unit is undergoing discharge temperature overheating protection. The error code is for Diamante series systems.</p><h2 id="troubleshooting-diagram"><u>Troubleshooting Diagram</u><u><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025111319-2a2889dc-7886-4031-9364-79426ea92925-wyt17_p4_troubleshooting.png" style="width: 1000px;" class="fr-fic fr-dib fr-bordered"></u></h2>

This error code indicates the outdoor unit is undergoing discharge temperature overheating protection.

P4 error code

Troubleshooting

Troubleshooting (Diamante Series)

Do I need to restart my unit manually after the power goes out?

How can I fix my indoor air handler when the unit is not turning On?

How do I determine which breaker size and wire is needed for my system?

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What is the difference between 115V and 230V systems?

Electrical Related General Queries

Does the fan for my system shut Off in Cooling mode?

Does my system include factory pre-charged refrigerant?

How can I check the resistance of a Pioneer temperature sensor?

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How do I apply Pioneer Flare Leak Guard during installation?

Pioneer lineset diameter selection guide

What are the requirements for installing a mini split?

What type of oil is used for my unit?

Why did my ductless mini split system freeze on the inside air handler?

Are the linesets pre-flared when I buy a mini split?

Diagnosing and Preventing Crossed Wiring in Multi-Zone Systems

Sizing Systems & Short Cycling

What Refrigerants do Pioneer HVAC Systems Use?

HVAC Related General Queries

Can a wall-mounted indoor unit be set onto the ceiling instead?

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What is the ideal height for mounting indoor units?

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Indoor Unit

Are there recommended resources to find a professional near me?

Can the lineset be angled upward?

What gauge of wire is used for connections between the ductless mini split indoor and outdoor sections?

What hole saw size do I need for drilling walls to accommodate drain and refrigerant lines?

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Online Shopping

PT Chart (YN012ALUI17RPD)

PT Chart (YN012GLUI17RPD)

PT Chart (YN018GLUI17RPD)

PT Chart (YN024GLUI17RPD)

PT Chart (YN036GLUI17RPD)

PT (Pressure-Temperature) Charts - WYT-17

Diamante Essenza - High Wall Mount (WYT-17)

PT Chart (YN009ALSI20RPF)

PT Chart (YN009GLSI20RPF)

PT Chart (YN012ALSI20RPF)

PT Chart (YN012GLSI20RPF)

PT Chart (YN018GLSI20RPF)

PT Chart (YN024GLSI20RPF)

PT Chart (YN030GLSI20RPF & YN036GLSI20RPF)

PT (Pressure-Temperature) Charts - WYT-20

Diamante Pro - High Wall Mount (WYT-20)

PT Chart (YN009ALSI24RPG)

PT Chart (YN009GLSI24RPG)

PT Chart (YN012ALSI24RPG)

PT Chart (YN012GLSI24RPG)

PT Chart (YN018GLSI24RPG)

PT Chart (YN024GLSI24RPG)

PT (Pressure-Temperature) Charts - WYT-24

Quantum Ultra - High Wall Mount (WYT-24)

PT Chart (YN009GLSI25RPH)

PT Chart (YN012GLSI25RPH)

PT Chart (YN018GLSI25RPH)

PT Chart (YN024GLSI25RPH)

PT (Pressure-Temperature) Charts - WYT-25

Quantum Hyperformance - High Wall Mount (WYT-25)

PT Chart (YN012GLUI25RPQ)

PT (Pressure-Temperature) Charts - WYT-FA

Quantum Fresh - High Wall Mount (WYT-FA)

PT (Pressure-Temperature) Charts - CYT-24

Quantum Ultra - Ceiling Cassette (CYT-24)

PT (Pressure-Temperature) Charts - RYT-24

Quantum Ultra - Ceiling Concealed (RYT-24)

PT (Pressure-Temperature) Charts - UYT-24

Quantum Ultra - Floor-Ceiling Flex (UYT-24)

PT Chart (YN020GLSI24M2G)

PT Chart (YN030GLSI24M3G)

PT Chart (YN040GLSI24M4G)

PT Chart (YN050GLSI24M5G)

PT (Pressure-Temperature) Charts - YNL-24

Multi-Zone Quantum Ultra

Technical Documentation (Diamante Series)

Pioneer Airlink App

Diamante Series Systems (WYT-19, WYT-22)

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Ducted Central Split DYR Series

NetHome Plus

RG10 Remote

Technical Documentation (Quantum Series)

Quantum Series Systems (WYS/CYB/RYB/UYB/FYB)

Discontinued Products

Products

CL error code

E0 error code

E1 or E2 error codes

E3, E7, or E8 error codes

E6 error code

E4 error code

E9 error code (Diamante Series)

E9 error code (Quantum Series)

EF error code

EU error code

F4 error code

F5 error code

PA error code (Multi-Zone Quantum Ultra Systems)

F6 error code

F7 error code

F8 error code

Fd error code

Fy error code

P0 error code

P1 error code

P2 error code

P5 error code

P6 error code

P7 error code

P8 error code

P9 error code

E9/P0 error codes

Indoor unit displaying 0A code

Troubleshooting (WYT-19 & WYT-22)

E1/EL 01/EL01 error codes

E3/EH 03/F5/EC 07 error codes

EC/EL 0C error codes

F4/EC51 error codes

LCAC error codes

P0/PC00 error codes

P1/PC01 error codes

P2/PC02 error codes

PC 03/PC03 error codes

P4/PC 04/PC04 error codes

Troubleshooting (WYS, CYB, RYB, UYB, & FYB)

Troubleshooting (Discontinued Products)

Introduction

Troubleshooting Diagram

P4 error codeUpdated 3 hours ago

Introduction

Troubleshooting Diagram