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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. This article is for Diamante and Quantum series systems.&#xA0;</p><h2 id="troubleshooting"><u>Troubleshooting</u></h2><p>After the power relay operates, if the tested effective voltage is less than 50v for 3 seconds continuously, the unit 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 outdoor unit voltage test sensor failure. This troubleshooting article is for Diamante and Quantum series systems.

EU Error Code

Troubleshooting

By Error Code

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Diamante Essenza (WYT-17) Overview

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Open Ceiling and Install Hanging Hook for Quantum Ultra Ceiling Cassette (CYT-24) Systems

Select the Indoor Unit Installation Location for Quantum Ultra Ceiling Cassette (CYT-24) Systems

Set Up the Indoor Unit Condensate Piping Connections for Quantum Ultra Ceiling Cassette (CYT-24) systems

Suspend the Air Handler Unit for Quantum Ultra Ceiling Cassette (CYT-24) Systems

Understand the Additional Leakage Sensor for Quantum Ultra Ceiling Cassette (CYT-24) Systems

Understand the Air Duct Parameters for Auxiliary Duct Usage

Cassette Units

Select the Indoor Unit Installation Location for Quantum Ultra Ducted Ceiling Concealed Systems

Select the Indoor Unit Installation Location for Vertex Ducted Central Split Systems

Understand the Additional Leakage Sensor for Quantum Ultra Ducted Ceiling Concealed (RYT-24) Systems

Ducted Units

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First-Time Setup

Angle Linesets Upward

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Find Out if a Wall-Mounted Indoor Unit can be Set onto Ceilings

Find Out if the Indoor Unit Requires Anything Extra in Order to be Wall-Mounted

Find Out the Ideal Height for Mounting Indoor Units

Learn the Gauge of Wire Used for Ductless System Connections

Setup the Lineset to Exit from the Side of the Indoor Unit

Understand 6-Foot Plastic Whips and 4-Lead Mini Split Connection Wire

Understand the Drilling Details to Accommodate Drain and Refrigerant Lines

Understand the Requirements for Installing Your System

Understand the Torque Wrench Size for Installing Your System

Installation Requirements

Understand the Meaning of “Multi-Zone”

Multi-Zone Units

Air Evacuation and Bleeding the Circuit for Wall-Mounted Systems

Connect the Drain Hose for Wall-Mounted Systems

Connect the Fresh Air Pipe for Quantum Fresh Systems

Connect the Power/Signal Electrical Wiring for Wall-Mounted Systems

Connect the Refrigerant Piping to the Indoor Unit for Wall-Mounted Systems

Connect the Refrigerant Piping to the Outdoor Unit for Wall-Mounted Systems

Drill the Piping Wall Hole for Wall-Mounted Systems

Install the Indoor Unit Mounting Plate for Wall-Mounted Units

Mount the Indoor Unit for Wall-Mounted Systems

Mount the Outdoor Unit for Wall-Mounted Systems

Prepare the Refrigerant Piping of the Indoor Unit for Wall-Mounted Systems

Select the Indoor Unit Installation Location for Quantum Fresh Systems

Select the Indoor Unit Installation Location for Quantum Ultra Floor-Ceiling Flex Systems

Select the Indoor Unit Installation Location for Wall-Mounted Systems

Select the Outdoor Unit Installation Location for Wall-Mounted Systems

Set Up the Outdoor Unit Condensate Water Drainage for Wall-Mounted Systems

Understand the Additional Leakage Sensor for Wall-Mounted Systems

Understand the Additional Leakage Sensor for Quantum Ultra Floor-Ceiling Flex (UYT-24) Systems

Single-Zone Units

Installation & Setup

Front Panel Displays for Quantum Ultra Ceiling Cassette Systems

Front Panel Display for Quantum Ultra Floor-Ceiling Flex Systems

Front Panel Displays for Wall-Mounted Systems

Wired Display Board Layout for Quantum Ultra Ducted Ceiling Concealed Systems

Display Layouts

CL error code

Clean the Anti-Dust Filters for Diamante Essenza and Pro Systems

Clean the Anti-Dust Filters for Quantum Ultra High Wall-Mount and Hyperformance Systems

Clean the Anti-Dust Filters for Quantum Fresh Systems

Cleaning the Anti-Dust Filters for Quantum Ultra Ceiling Cassette Systems

Clean the Anti-Dust Filters for Quantum Ultra Ducted Ceiling Concealed Systems

Clean the Anti-Dust Filters for Quantum Ultra Floor-Ceiling Flex Systems

Filter Cleaning & CL Code

Determine the Breaker Size and Wire Needed for Your System

Diagnose and Prevent Crossed Wiring in Multi-Zone Systems

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Electrical Related Queries

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Turn Off the LED Display for the Indoor Unit

General Queries

Check the Resistance of a Pioneer Temperature Sensor

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HVAC Related Queries

Maintenance Tips

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

Activate Gentle Wind Mode

Activate Heating Mode

Activate the I Feel feature

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Turn the LED Display On or Off

Control the Airflow for Ceiling Cassette Systems

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Control System Airflow

Operating Instructions

Activate Heat Mode Using Diamante Pro Series Remotes

Replace Batteries for Remote Controls

Use the Emergency Manual Button to Operate the Indoor Unit Without a Remote Control

EU Error CodeUpdated a day ago

Introduction

Troubleshooting

Troubleshooting Diagram