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<h2 id="introduction"><u>Introduction</u></h2><p>The &quot;EU&quot; error code indicates the outdoor unit&apos;s voltage test sensor has experienced a fault.&#xA0;</p><p id="isPasted"><span style="font-size: 16px;">This article is for the following systems:&#xA0;</span></p><ul><li style="font-size: 16px;"><a href="https://www.pioneerminisplit.com/collections/types?q=WYT-17" target="_blank" rel="noopener noreferrer">Diamante Essenza High-Wall (WYT-17)</a></li><li style="font-size: 16px;"><a href="https://www.pioneerminisplit.com/collections/types?q=WYT-20U" target="_blank" rel="noopener noreferrer">Diamante Essenza High-Wall (WYT-20U)</a></li><li style="font-size: 16px;"><a href="https://www.pioneerminisplit.com/collections/diamante-pro-high-wall-series" target="_blank" rel="noopener noreferrer">Diamante Pro High-Wall (WYT-20S)</a></li><li style="font-size: 16px;"><a href="https://www.pioneerminisplit.com/collections/types?q=WYT-24" target="_blank" rel="noopener noreferrer">Quantum Ultra High-Wall (WYT-24)</a></li><li style="font-size: 16px;"><a href="https://www.pioneerminisplit.com/collections/types?q=WYT-25" target="_blank" rel="noopener noreferrer">Quantum Hyperformance High-Wall (WYT-25)</a></li><li style="font-size: 16px;"><a href="https://www.pioneerminisplit.com/collections/quantum-fresh-series-breathe-the-difference" target="_blank" rel="noopener noreferrer">Quantum Fresh High-Wall (WYT-FA)</a></li><li style="font-size: 16px;"><a href="https://www.pioneerminisplit.com/collections/types?q=CYT-24" target="_blank" rel="noopener noreferrer">Quantum Ultra 8-Way Ceiling Cassette (CYT-24)</a></li><li style="font-size: 16px;"><a href="https://www.pioneerminisplit.com/collections/types?q=RYT-24" target="_blank" rel="noopener noreferrer">Quantum Ultra Ducted Ceiling Concealed (RYT-24)</a></li><li style="font-size: 16px;"><a href="https://www.pioneerminisplit.com/collections/types?q=UYT-24" target="_blank" rel="noopener noreferrer">Quantum Ultra Universal Floor-Ceiling Flex (UYT-24)</a></li></ul><p>After the power relay operates, if the tested effective voltage is less than 50V for 3 seconds continuously, the system will display the error code.&#xA0;</p><h2 id="troubleshooting-diagram"><u>Troubleshooting Diagram</u><u><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025111318-5a55541a-5bd6-4c98-98c7-f8c4175356d0-wyt17_eu_troubleshooting.png" style="width: 1000px;" class="fr-fic fr-dib fr-bordered"></u></h2><h2 id><br></h2>

This error code indicates the outdoor unit's voltage test sensor has experienced a fault.

EU Error Code

Troubleshooting

By Error Code

Diamante & Quantum Systems

Pioneer Offers Hyper-Heat Units

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Understanding the Difference Between 115V & 230V Systems

Understanding the Refrigerants Used for Each Model

How to Choose a System

Does Pioneer Offer Pre-Charged Linesets?

Does Pioneer Offer Pre-Flared Linesets?

How Mini-Splits Are Powered

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Pioneer Mini-Splits Function as Dehumidifiers

Pioneer Offers Various Lineset Lengths

Pioneer Systems Feature Factory Pre-Charged Refrigerant

Running a Mini-Split Below Its Total Zone Capacity

Single-Zone Mini Splits Cannot Be Used with Multiple Indoor Units

Understanding the Allowable Zone Combinations for Multi-Zone Systems

Understanding the Life Expectancy of Pioneer Systems

Mini-Split Basics

Determining the Unit Size Needed for Your Space

How System Sizing Causes Short Cycling

Matching the Lineset Diameter to Your Pioneer Indoor Unit

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Diamante Essenza High-Wall (WYT-17) Overview

Diamante Essenza High-Wall (WYT-20U) Overview

Diamante Pro High-Wall (WYT-20S) Overview

Quantum Fresh High-Wall (WYT-FA) Overview

Quantum Hyperformance High-Wall (WYT-25) Overview

Quantum Ultra 4-Way Ceiling Cassette (CYB-20) Overview

Quantum Ultra 8-Way Ceiling Cassette (CYT-24) Overview

Quantum Ultra Ducted Ceiling Concealed (RYB-20) Overview

Quantum Ultra Ducted Ceiling Concealed (RYT-24) Overview

Quantum Ultra Floor-Ceiling Flex (UYB-20) Overview

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

Quantum Ultra Floor/Low-Wall Mounted Console (FYB-20) Overview

Quantum Ultra High-Wall (WYT-24) Overview

Quantum Ultra Multi-Zone (YNL-24) Overview

Quantum Ultra Single-Way Ceiling Cassette (CYK-24) Overview

Vertex Ducted Central Split (DYC-18) Overview

Ducted & Ductless Systems

ECOasis 50 Ductless Wall-Mounted Single-Room Energy Recovery Ventilator (ERV) Overview

ECOasis 150 Ductless Wall-Mounted Single-Room Energy Recovery Ventilator (ERV) Overview

Energy Recovery Ventilators

QHD070 Whole-House Ducted Dehumidifier (QHD) Overview

High Performance Dehumidifier

Full Inverter Rooftop RV Air Conditioner Heat Pump (PYZ) Overview

Under-Bench RV Inverter Packaged Heat Pump Air Conditioner (PYR) Overview

Recreational Vehicle Systems

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Can Wall-Mounted Indoor Units Be Installed on the Ceiling Instead?

Does the Indoor Unit Need Additional Hardware for Wall Mounting?

General Installation FAQ

Conducting Test Runs

Connecting the Refrigerant Piping

Drilling Requirements for Installing Drain & Refrigerant Lines

Evacuating the Refrigerant Circuit

Selecting the Correct Standard Wire Gauge for Connections

Understanding the Differences Between a 6-Foot Plastic Whip & a 4-Lead Wire

Understanding the Ideal Mounting Height for Indoor Units

Understanding Refrigerant Lineset Installation

Understanding the Requirements for Installing Wall-Mounted Systems

Drainage Tests

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Ceiling Cassettes

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Ducted Central Split

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Indoor Units

Installing Outdoor Units: Getting Started

Selecting the Installation Location for Outdoor Units

Installing the Drain Joint for Outdoor Units

Mounting the Outdoor Unit

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Outdoor Units

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Installing ECOasis 50 Energy Recovery Ventilators

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Energy Recovery Ventilator

Connecting the Drain Fitting for QHD070 Whole-House Ducted Dehumidifiers

High Performance Dehumidifiers

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Rooftop RV Inverter

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Creating the Floor Openings for Under-Bench RV Systems

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Creating the Recirculation Air Opening for Under-Bench RV Systems

Understanding the Ductwork Best Practices for Under-Bench RV Systems

Connecting & Powering Up Under-Bench RV Systems

Under-Bench RV Inverter

Installation

Understand the DIP Switches for Vertex Ducted Central Split Systems

DIP Switch Layouts

Turn the LED Display On or Off

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CL Error Code

Clean the Filters for 4-Way & 8-Way Ceiling Cassette Systems

Clean the Filters for Diamante Wall-Mounted Systems

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Clean the Filters for Quantum Fresh High-Wall Systems

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Clean the Filters for Quantum Ultra Universal Floor-Ceiling Flex Systems

Clean the Filters for Quantum Ultra & Hyperformance High-Wall Systems

Clean the Filter Screen for Rooftop RV Systems

Clean the Filters for Single-Way Ceiling Cassette Systems

Clean the Filters for Under-Bench RV Systems

Filter Cleaning & CL Code

Activate Auto Mode

Activate the Child-Lock Function

Activate Cooling Mode

Activate Dry Mode

Activate Energy Saver (ECO) Mode

Activate Fan-Only Mode

Activate the Fresh Air Feature for Quantum Fresh High-Wall Systems

Activate Gentle Wind Mode for Quantum Fresh High-Wall Systems

Activate Heating Mode

Activate the I Feel Feature

Activate the Memory Feature

Activate Mute Mode

Activate the Self-Clean Feature

Activate Sleep Mode

Activate the Timer On/Timer Off Function

Activate Turbo Mode

Activate 46°F Freeze Protection

Understand the Auto-Restart Feature

Understand the Voice Control Feature For Quantum Fresh High-Wall Systems

Understand the Defrost Function

Understand the Dehumidification Function

Understand the Drainage Functions

QHD070 Whole-House Dehumidifiers

Activate Dehumidification Mode

Activate Night Mode

Activate Ventilation Mode

Rooftop RV Systems

Under-Bench RV Systems

Activate the Accelerated Cooling/Heating Function

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Understand the Compressor Crankshaft Heater Control Function

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Understand the Passive Dehumidification Function

Understand the Refrigerant Leak Detection Function

Vertex Ducted Central Split Systems

Functions & Modes Explained

Determine the Breaker Size & Wire Needed for Your System

Diagnose & Prevent Crossed Wiring in Multi-Zone Systems

Understand how the System Receives Power

Electrical Related Queries

Maintenance Tips

Operation & Usage

EU Error CodeUpdated 14 days ago

Introduction

Troubleshooting Diagram