Star-supply
star-supply.com › content › Daikin Single- Multi -U4 Error Code.pdf pdf
Daikin Single-Multi U4 Error Codes
U4 Error Codes · Only good for Daikin Single Zones & Multi-Splits-NOT VALID ON VRV OR SKYAIR · *Always refer to the Service Manual for proper procedures* U4 Fault code is a Signal Transmission Error (between Indoor Unit and Outdoor Unit) REQUIRED TOOLS: MEGGER, MULTIMETER WITH MICRO LEADS ·
JustAnswer
justanswer.com › hvac › bvmqb-u4-error-daikin-indoor-unit-keeps.html
Daikin U4 Error Code: Expert Solutions and Fixes
December 27, 2018 - The U4 error on Daikin units often indicates a fan motor or flap actuator malfunction. First, power off and vacuum dust from the indoor unit’s fan and flap mechanisms. Check for obstructions preventing flap movement.
I have a Daikins inverter that is giving a U4 error code. I
I have a Daikins inverter that is giving a U4 error code. I turned off the power, let stand 5 min, restarted and it More on justanswer.com
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August 3, 2024[Daikin VRV] [220 VAC] U4-01 Error Code Help
They have their own specific setup that I can’t remember (too many schematics in my brain). If it runs for a little bit and then shuts off for a while, kicks on for a bit and yada yada, check your condensate line, might be tripping a “safety switch.” Thats a quick fix, vacuum out the line. Check around the condenser and see if there’s a bunch of droppings. Rodents like to keep warm and chew on wires, those little bastards. Could be a number of things. But I’d start with the condy line. More on reddit.com
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September 6, 2024Daikin Mini split- error code U4
There’s a specific process to it. Need a Daikin d checker tool to really further diagnose More on reddit.com
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November 25, 2023Daikin Split AC unit blinking green light, troubleshooting shows no issue
may the gods bless all of you because i have been sweating my arse off for weeks trying to figure this out and i literally just had to turn it off and back on again... More on reddit.com
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August 3, 2021Videos
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Daikin U4 Error — You Already Know What This Is - YouTube
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Daikin VRV U4 Error Code - The Process for Success - YouTube
Repairing Daikin U4 Error
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Daikin Mini Split AC U-4 Error Fix - YouTube
Airway Group
airway-group.co.uk › home › help & advice › daikin air conditioning fault codes explained [infographic]
Daikin Air Conditioning Fault Codes Explained [Infographic] | Airway
April 2, 2026 - U4 – Communication error between indoor and outdoor units/outdoor and BS units – A mistake with the interconnection wires, or an indoor/outdoor PCB fault.
Star-supply
star-supply.com › content › Daikin-Troubleshooting Codes.pdf pdf
Trouble Shooting www.climatecenter.co.uk Daikin Trouble Shooting Guide
www.climatecenter.co.uk · Daikin Trouble Shooting Guide
AirReps
airreps.com › 2025 › 11 › understanding-the-u4-error-code-in-daikin-vrv-systems
Understanding the U4 Error Code in Daikin VRV Systems - AirReps
November 19, 2025 - The U4 error code indicates a communication failure between the indoor unit and outdoor unit. Essentially, your system components are having trouble “talking” to each other through the transmission wiring that connects them.
Scribd
scribd.com › document › 425197901 › Daikin-error-code-pdf
Daikin VRV Error Code Troubleshooting Guide | PDF | Manufactured Goods | Electrical Engineering
Check whether the capacity setting adapter is correct and the type of the PC board for the fan is correct. Troubleshooting Troubleshooting Error code Description of error Description of diagnosis U4 − 01 Indoor-Outdoor transmission error Refer to the “U4” flow chart.
Daikin
my.daikin.eu › content › dam › DASW › supportavdelningen › Felkoder_SM-TS3errorcode_chart.pdf pdf
Simple Self-Diagnosis by Malfunction Code After Sales Service Division (SM-TS3)
“long beep” sound are error code. 8. Press the MODE button to exit from the · diagnosis mode. The display “ ” means the trial operation · mode. 9. Press the ON/OFF button twice to return · to the normal mode. Note: When the remote controller is left untouched · for 60 seconds, it returns to the normal mode. No. 1 · 2 · 3 · 4 · 5 · 6 · 7 · 8 · 9 · 10 · 11 · Code · 00 · U4 ·
Daikin
daikin.com › products › ac › services › error_codes
Error Codes | After Sales Service | Air Conditioning and Refrigeration | Daikin Global
By checking the error code, you are able to identify the status and the issue of the air conditioner/air conditioning system.
Daikin India
daikinindia.com › product-services › product-services › error-codes
Error Codes | Daikin
Fault diagnosis by remote controller The remote controller can receive relevant error codes from the indoor unit.
ADK Kooling
adk.co.uk › home › air conditioning › daikin error code u4 — vrv communication fault explained
Daikin Error Code U4 | Communication Fault Fix | ADK London
March 23, 2026 - Daikin VRV showing U4 error code? It's a communication fault between indoor and outdoor units. Common causes and fixes explained. Call ADK London.
Daikin
daikin.com › - › media › Project › Daikin › daikin_com › products › ac › services › error_codes › pdf › sm-ts3_p7-8_howtocheck-pdf.pdf pdf
UNIT NO. 1 CODE UNIT NO. 1 3. Press MODE selector button. 4. Change the
“long beep” sound are error code. 8. Press the MODE button to exit from the · diagnosis mode. The display “ ” means the trial operation · mode. 9. Press the ON/OFF button twice to return · to the normal mode. Note: When the remote controller is left untouched · for 60 seconds, it returns to the normal mode. No. 1 · 2 · 3 · 4 · 5 · 6 · 7 · 8 · 9 · 10 · 11 · Code · 00 · U4 ·
HVAC Toolkit
hvactoolkit.org › home › resources › error codes › daikin
Daikin Error Codes - Complete Fault Code List & Solutions | HVAC Toolkit
Complete Daikin error code list for mini-splits, VRV systems, and air conditioners. Find meanings, causes, and troubleshooting solutions for all Daikin fault codes.
JustAnswer
justanswer.com › hvac › pphzc-daikins-inverter-giving-u4-error-code.html
Daikin Inverter U4 Error Code? Expert Troubleshooting Guide
August 3, 2024 - ... Inverter systems often face sensor faults and communication errors causing startup failure. The U4 error on a Daikin inverter typically indicates a communication or sensor fault.
Pick Comfort
pickcomfort.com › home › daikin heat pump error codes guide
Daikin Heat Pump Error Codes Guide - Pick Comfort
December 26, 2025 - Daikin heat pump error codes help diagnose issues quickly and reduce downtime. This guide explains common codes, their meanings, troubleshooting steps, and when to call a professional. It focuses on residential Daikin systems and provides actionable advice for safe diagnostics and repairs.
Reddit
reddit.com › r/hvacadvice › [daikin vrv] [220 vac] u4-01 error code help
r/hvacadvice on Reddit: [Daikin VRV] [220 VAC] U4-01 Error Code Help
September 6, 2024 -
My air conditioning failed on me some time today when I was at work, and when I returned home it was 92° inside my home. Figures this would happen during the (hopefully) hottest week of the year in Los Angeles. This system was professionally installed in June of 2020, and has worked without issue until now. The company that did it was bought out by another larger firm, and they are unable to send a tech out for another 17 days. I’m kind of SOL there. I change the filters every six months in the air handlers, and regularly hose down/clean the exterior unit. With a basic visual inspection, it does not appear that there are any blockages/impediments to air flow. I have tried powering off both the exterior unit and both interior air handlers by switching off the breakers on two separate occasions. The cooling works for about 10 minutes and then the error message is displayed again on the interior control panel. Any ideas?
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They have their own specific setup that I can’t remember (too many schematics in my brain). If it runs for a little bit and then shuts off for a while, kicks on for a bit and yada yada, check your condensate line, might be tripping a “safety switch.” Thats a quick fix, vacuum out the line. Check around the condenser and see if there’s a bunch of droppings. Rodents like to keep warm and chew on wires, those little bastards. Could be a number of things. But I’d start with the condy line.
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So the error you're getting is for the loss of communication between the indoor and outdoor unit. Usually you would get this immediately if the communication wire actually has an issue, but since the unit runs and cools for 10 mins that's kind of giving the sign of power loss at the outdoor unit at the 10ish min mark. Sadly I think there is more to your issue than just this error code.
HVAC In Expert
hvacinexpert.com › home › daikin ac error codes list
Daikin AC Error Codes List
April 14, 2026 - If your AC suddenly stops cooling and displays a strange code like U4, A5, L5, E6, don’t panic. This complete guide explains the Daikin AC error codes list, meaning, causes, step-by-step solutions, and difficulty level so you can understand:
Heatncooltech
heatncooltech.com.au › wp-content › uploads › 2023 › 02 › Error-code-check-1.pdf pdf
How To Find the Fault Code on a Daikin Split System
Once the code is found, it can be looked up using the Daikin error code chart. 1. For example, the error code U4 was found above, with the chart showing
Airchillac
airchillac.com › daikin-ac-error-codes
Daikin AC Error Codes Guide – Fixes, and Troubleshooting Tips | AirChill AC Maintenance and Duct Cleaning
June 5, 2025 - In this article, you’ll learn what these Daikin air conditioner error codes mean, how to read them, and how to fix them.