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<div data-block="true" data-editor="8h0ar" data-offset-key="3g900-0-0" id="isPasted"><h2 id="isPasted"><u>Introduction</u></h2><p>The &#x201C;F4&#x201D; or &#x201C;EC51&#x201D; error codes indicate the indoor or outdoor PCB main chip is not receiving feedback from the EEPROM chip. The error codes are for Quantum Series systems.&#xA0;</p><h2 id="prerequisites"><u>Prerequisites</u></h2><p>Recommended parts to prepare:</p><ul><li style="font-size: 16px;">Indoor Printed Circuit Board (PCB)</li><li style="font-size: 16px;">Outdoor Printed Circuit Board (PCB)</li></ul><h2 id="troubleshooting"><u>Troubleshooting</u></h2><p><strong id="isPasted">Note</strong>: You may require an HVAC professional for assistance.</p><p>The troubleshooting recommendations include:</p><ul><li style="font-size: 16px;">Power Off the unit and restart it after 2 minutes.&#xA0;</li><li style="font-size: 16px;">Check if the error code is still displaying.</li><li style="font-size: 16px;">Replace the outdoor mainboard if the error is still displaying.</li></ul><p><strong>Note</strong>: Contact our Parts and Warranty department for any replacement components. Call 1-800-919-0150; Option #4.</p><h2 id="troubleshooting-diagram"><u>Troubleshooting Diagram</u></h2></div><div data-block="true" data-editor="8h0ar" data-offset-key="23bnm-0-0" style="box-sizing: border-box; -webkit-font-smoothing: antialiased; color: rgb(34, 34, 34); font-family: Inter, &quot;Helvetica Neue&quot;, Arial, Helvetica, sans-serif; font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;"><p><span data-offset-key="23bnm-0-0" style="box-sizing: border-box; -webkit-font-smoothing: antialiased;"><span data-text="true" style="box-sizing: border-box; -webkit-font-smoothing: antialiased;"><img src="https://attachments.gorgias.help/aalb/hc/qb0/ec%2051-49f384ad-edc8-4dd4-bb7f-42ffe7cf1de5.png" style="width: 545px;" class="fr-fic fr-dib fr-bordered"></span></span></p></div>

Figure out how to resolve "F4" or "EC51" error codes for Quantum Series systems by reading this troubleshooting article. 

Troubleshoot F4 or EC51 error codes for Pioneer units

Products

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

Error Code Troubleshooting (Quantum 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?

How does my system receive power?

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?

How can I fix leaks that are difficult to trace?

How can I locate the Pioneer model or serial number for my system?

How do I apply Pioneer Flare Leak Guard during installation?

Is there a 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?

HVAC Related General Queries

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

Can I operate the indoor unit without a remote control?

Can I turn Off the LED display for the indoor unit?

Can the lineset exit from the side of the indoor unit?

Does the indoor unit require anything extra in order to be mounted to the wall?

What is the ideal height for mounting indoor units?

What is the indoor unit’s weight and dimensions?

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?

What is the cost and time spent on installing systems?

What torque wrench size do I need?

Where can I find wire-related information?

Who is permitted to install the A/C?

Installation

Why is my mini split leaking water improperly?

Plumbing and Drainage Queries

How can I access manuals and technical documents?

What is the telephone number to receive Tech Support?

Technical Support

General Technical Questions

Can a single-zone mini split be used with multiple indoor units?

Can I buy a Pioneer system that only offers cooling?

Can I order different lineset lengths?

Do these split-type systems function as dehumidifiers?

Do you carry hyper-heat units (-22°F)?

Do you offer any discounts?

Do you offer pre-charged linesets?

How can I obtain spare parts?

How do I determine the unit size needed for my space?

How do I find an installer for my Pioneer Mini Split purchase?

How do I make a return?

How do I use my Pioneer Rewards Points when shopping?

How does the Energy-Star Federal Tax Credit work for Pioneer systems?

How do the units receive power?

What does “multi-zone” mean?

What is the difference between Inverter+ and Inverter++ systems?

What is the life expectancy of my system?

What is the Qualified Manufacturer ID for Parker Davis HVAC International?

What types of refrigerants are used in the new models?

Where can I learn more about IRA tax credits?

Which units are rated Energy-Star?

Why do I see multiple charges on my credit card?

Why does the discount code only say "SAMPLE" when trying to refer friends?

Can I use a mini-split system with fewer indoor units than the outdoor unit's zonal capacity?

Frequently Asked Questions

Process for returning an item

Refund eligibility requirements

Return an item

Return fees

Return policy

Start your return

Undeliverable or refused shipments

Returns and Refunds

Free shipping qualifications

Shipping and delivery details

What should I do if I receive an email saying my package was delivered, but I haven't received it?

Shipping and Delivery

Warranty coverage

Warranty durations

Warranty

Online Shopping

Error Code E0

Error Code E9/P0

Error Code FY

Indoor unit displaying 0A code

How can I address a "PA" error code on my multi-zone Diamante Ultra unit?

Error Code Troubleshooting (Diamante Series)

Understand the difference between Diamante Pro and Diamante Ultra systems

Wall Mounted WYT-19 Diamante Pro Series

Wall Mounted WYT-22 Diamante Ultra Series

Technical Documentation (Diamante Series)

Connect your WYT-19 Diamante Series with the Pioneer Airlink App

Connect your WYT-22 Diamante Series with the Pioneer Airlink App

Integrate the Pioneer Airlink App with Apple's Smart Home Environment

Pioneer Airlink App

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

Understand how Cased A-Coils interact with furnaces and other heating units

Technical Documentation (DYR Series)

Ducted Central Split DYR Series

Error Code CL

Error Code E1/EL 01/EL01

Error Code E3/EH 03/F5/EC 07

Error Code EC/EL 0C

Error Code F4/EC51

Error Code P0/PC00

Error Code P1/PC01

Error Code P2/PC02

Error Code PC 03/PC03

Error Code P4/PC 04/PC04

Interpret LCAC error codes

Connect CYB, RYB, and UYB systems with the NetHome Plus App

Connect WYS-20 and WYS-22 systems with the NetHome Plus App

NetHome Plus

Switch between °F and °C on the RG10 remote

RG10 Remote

CYB Ceiling Cassette

RYB Ceiling Concealed

WYS Wall Mounted

Technical Documentation (Quantum Series)

Introduction

Prerequisites

Troubleshooting

Troubleshooting Diagram

Error Code F4/EC51Updated 2 hours ago

Introduction

Prerequisites

Troubleshooting

Troubleshooting Diagram