Why Is My Daikin Air Conditioner Not Turning Off?
A Daikin air conditioner not turning off can mean one of two quite different things. Either the system is working correctly and running because the room genuinely has not reached the set temperature, or something is preventing the normal off cycle from occurring even when the temperature conditions for a shutdown have been met. Identifying which situation applies is the essential first step.
Daikin reverse cycle air conditioners are designed to run continuously when there is a gap between the current room temperature and the set temperature on the remote. During Melbourne's peak summer days, it is not unusual for a correctly functioning system to run for extended periods because the heat entering the room is continuously replacing what the system removes. This is not a fault. A fault exists when the system continues running after the room has clearly reached and passed the set temperature, or when pressing the off button produces no response.
This guide covers both categories, explains the causes of each, provides a structured set of checks to perform at home, and identifies the situations where a certified Daikin technician in Melbourne needs to diagnose the underlying issue.
Before investigating any fault, confirm the actual room temperature against the set temperature on the remote. If the room is still warmer than the setpoint, the system running continuously is normal behaviour. If the room has clearly passed the setpoint and the system is still running, or if the off button is producing no response, there is a genuine fault to investigate.
Is It Normal for a Daikin AC to Keep Running? How to Tell the Difference
Understanding which running patterns are normal and which indicate a fault prevents unnecessary service calls and helps identify when professional attention is genuinely needed.
Running Patterns That Are Normal and Expected
- Running continuously during Melbourne heatwave conditions when outdoor temperatures are extreme and the room heat load is very high
- Running for extended periods when the system is first turned on and the room is significantly warmer than the setpoint, particularly if the room has been unoccupied all day
- Running the fan for a brief period after the compressor cycles off, to distribute the residual cooling from the evaporator coil
- Running in fan-only mode continuously if set to that mode, as fan-only mode does not have a temperature-based shutoff
- Running continuously because the setpoint was set to a very low temperature that requires sustained operation to maintain in a warm environment
- Running the indoor fan during a heating mode defrost cycle while the outdoor unit defrosts, which can last up to fifteen minutes
Running Patterns That Indicate a Fault
- The room is clearly below the set temperature but the system continues to run and cool
- The off button on the remote is pressed but the system does not respond and continues to run
- The manual off button on the indoor unit body produces no response
- The system was off but has restarted by itself without any user input or active timer
- The system runs continuously at all times regardless of the room temperature relative to the setpoint
- The system runs for significantly longer periods between off cycles than it did previously under the same conditions
- The room temperature has dropped below the setpoint and the system has not cycled off within a reasonable period
Every Cause of a Daikin AC Not Turning Off or Keeps Running
These are the causes our Melbourne Daikin technicians identify when called out for a Daikin air conditioner that will not stop running or will not respond to off commands. They are listed from the most common and straightforward through to those requiring professional diagnosis.
Daikin Timer Setting Problem
A Daikin timer setting preventing the unit from turning off is the first thing to check when a system appears to run beyond the expected period. A continuous run timer or a scheduled on time that has been set without a corresponding off time will keep the system operating indefinitely until the timer is cancelled. Check the remote display carefully for any timer indicator, a scheduled run mode icon, or a continuous operation setting. Cancelling an accidentally activated continuous run mode takes seconds and resolves the issue immediately if that is the cause.
Daikin AC Thermostat Issue, Room Not Reaching Setpoint
A Daikin AC that runs continuously because the room genuinely cannot reach the set temperature is not technically a fault in the system, but it indicates either a performance issue or an environmental condition that needs addressing. A system with low refrigerant, a dirty condenser coil, or a room with very high heat gain from poor insulation or large sun-exposed windows may run without achieving the setpoint. In this case the system is doing exactly what it is designed to do, it simply does not have sufficient capacity to overcome the heat load at the set temperature. Reducing the heat load or servicing the system are the appropriate responses.
Daikin AC Sensor Problem, Faulty Thermistor
A faulty indoor room temperature thermistor is one of the most common causes of a Daikin AC running continuously without turning off even when the room has clearly reached and passed the set temperature. The thermistor is the sensor that reports the current room temperature to the control board. If the thermistor develops a resistance fault that causes it to report a higher temperature than the actual room reading, the control board never receives the signal that the setpoint has been achieved and the system runs indefinitely. Thermistor faults require resistance testing by a certified Daikin technician and are resolved by replacing the faulty sensor.
Daikin Remote Not Turning Off AC
When pressing the off button on the Daikin remote produces no response, the issue is either with the remote itself or the signal path between the remote and the indoor unit receiver. Flat remote batteries, a blocked signal path, a dirty receiver lens, or a failed remote transmitter can all prevent the off command from reaching the unit. Try pointing the remote directly at the indoor unit from within two metres and pressing off. If the unit still does not respond, try the manual off button on the indoor unit body to determine whether the issue is the remote or the unit itself.
Daikin Control Board Issue
A Daikin control board issue preventing the off cycle from executing is a more serious fault that occurs when the main PCB inside the indoor unit develops a logic fault affecting the on and off control function. The board continues to supply power to the fan and compressor but the circuit that processes the off command and triggers the shutdown sequence has malfunctioned. This type of fault produces a very specific pattern: the unit runs continuously, does not respond to the off button from either the remote or the manual button on the unit body, and the only way to stop it is to cut power at the circuit breaker.
Daikin AC Stuck in Cooling Mode
A Daikin AC stuck in cooling mode after a reset or a power event can result from a corrupted operating state stored in the control board memory. In some cases a power interruption or a voltage event can leave the system in an active mode state that persists even when commands to switch off are sent. A full power reset by switching the circuit breaker off for thirty seconds and restoring power can clear this corrupted state in many cases. If the unit returns to continuous running after the reset, the control board requires a technician to assess whether a firmware or hardware fault is responsible.
Daikin AC Not Turning Off, Symptom by Symptom Diagnosis
Use this table to match what you are observing with the most likely cause and the right first action.
| What You Observe | Most Likely Cause | First Action | DIY |
|---|---|---|---|
| Runs continuously, room is still above setpoint | Normal operation, room has not reached set temperature | Reduce heat gain, lower setpoint, check if outdoor is over 35 degrees | Normal |
| Runs continuously, remote shows continuous or timer mode | Active continuous run or timer setting on remote | Cancel the timer or continuous run mode on the remote | Yes |
| Runs even though room is clearly below setpoint | Faulty indoor thermistor reporting higher than actual temperature | Contact certified Daikin technician for thermistor resistance test | Tech needed |
| Remote off button produces no response | Flat batteries, blocked signal, or failed remote transmitter | Replace batteries, try manual off button on unit, clean receiver lens | Yes |
| Neither remote nor manual button stops the unit | Control board fault or stuck operating state | Switch circuit breaker off to force shutdown, contact Daikin technician | Partial |
| System restarts by itself after being turned off | Active timer scheduled to restart, or control board restart fault | Check remote for active timer, contact Daikin technician if no timer present | Partial |
| Runs longer between cycles than previously | Reduced cooling performance from low refrigerant or dirty coil | Clean filter, contact Daikin technician for refrigerant pressure test | Partial |
| Unit won't turn off after a reset | Thermistor fault or PCB control logic fault | Contact certified Daikin technician for thermistor and PCB diagnostic | Tech needed |
How to Fix a Daikin Air Conditioner That Will Not Turn Off, Step by Step
Work through these steps in order. The majority of Daikin not-turning-off complaints are resolved within the first three steps without professional involvement.
Confirm the Room Temperature Against the Setpoint
Check the current room temperature using a separate thermometer if possible, or reference an independent temperature source such as a smart home sensor or a weather station reading. Compare this to the setpoint on the Daikin remote. If the room temperature is still above the setpoint, the system is running normally and has not yet reached its target. In this case the solution is to reduce heat gain in the room, lower the setpoint, or allow more time for the system to overcome the heat load.
Check the Remote for Any Timer or Continuous Run Setting
Examine the remote display carefully for any timer indicator, a continuous run symbol, or any clock-based scheduling icon. Some Daikin remotes have a separate continuous run function that keeps the system operating until manually cancelled. Cancel any active timer or continuous setting using the remote manual instructions for your specific model. Once cancelled, press the off button and observe whether the system stops normally.
Press the Off Button Directly in Front of the Indoor Unit
Stand within two metres of the indoor unit and point the remote directly at the signal receiver on the front of the unit. Press the off button firmly. If the remote batteries are low, the signal may not be strong enough to reach the receiver reliably from across the room but may work from close range. If the unit shuts off when the remote is used close up but not from the normal operating distance, replace the remote batteries.
Try the Manual Off Button on the Indoor Unit
Locate the manual on/off button on the indoor unit body, typically behind the front panel or on the side of the unit. Press this button to attempt a direct shutdown without using the remote. If the unit responds to the manual button but not the remote, the remote has a fault. If neither the remote nor the manual button stops the unit, the fault is within the control board and the only way to stop the system is to cut power at the circuit breaker.
Perform a Full Power Reset via the Circuit Breaker
If the unit cannot be stopped by any button input, go to the switchboard and switch the air conditioner circuit breaker firmly to the off position. Wait thirty seconds. Switch the breaker back to on. Wait two minutes before attempting to use the remote. If the unit starts again immediately without any remote input and continues to run, there is a persistent control board fault that requires a certified Daikin technician to diagnose. Do not leave a system running unattended if you believe it has a control board fault.
Contact a Certified Daikin Technician in Melbourne
If the unit continues to run when it should not, restarts after being switched off, or will not respond to any off command after a full power reset, the fault requires professional diagnosis. A thermistor resistance test will confirm whether the indoor temperature sensor is providing an incorrect reading. A PCB diagnostic will identify whether the control board's on/off logic has developed a fault. Share what you observed during the steps above when you contact the technician, particularly whether the unit responded to the manual button or the circuit breaker reset.
Daikin AC Sensor Problem, How a Thermistor Fault Causes Continuous Running
The indoor room temperature thermistor is a small but critical component in the Daikin control system. Understanding how a thermistor fault produces the specific behaviour of a Daikin AC that keeps running helps confirm whether this is the cause of your situation.
How the Thermistor Controls the Off Cycle
The indoor room temperature thermistor continuously measures the temperature of the air returning to the indoor unit through the intake. It reports this reading to the main control board as a resistance value that corresponds to a specific temperature. The control board compares this reading to the setpoint on the remote. When the thermistor reading drops to the setpoint, the control board cycles the compressor off and the system enters a standby state, waiting for the temperature to rise again before restarting.
This process is the normal thermostat cycling behaviour of every Daikin reverse cycle system. When the thermistor is functioning correctly, the cycle happens reliably and the system maintains the setpoint temperature without running continuously.
What a Faulty Thermistor Does
When the thermistor develops a resistance fault, it provides a reading that is offset from the actual temperature. If the fault causes the thermistor to report a higher temperature than the actual room reading, the control board never sees the temperature drop to the setpoint, and the system runs continuously because it believes the room is still warm.
- The room may be noticeably cooler than the setpoint but the system keeps running
- The system may produce air that feels significantly colder than the setpoint suggests it should
- The fault is often intermittent early in its development, with the system occasionally cycling off normally before the thermistor reading drifts again
- Thermistor faults develop gradually and may go unnoticed until the offset is large enough to prevent the off cycle entirely
- The fault is confirmed through resistance testing by a certified Daikin technician and resolved by replacing the thermistor
Daikin AC Won't Turn Off, Specific Scenarios Explained
The pattern of how a Daikin unit keeps running provides useful information about the underlying cause. Matching your situation to the relevant scenario helps identify the right response.
Keeps Running After Reaching Temperature
A Daikin AC that keeps running even after the room has clearly reached and surpassed the setpoint is almost certainly experiencing a thermistor fault. The control board is not receiving the correct temperature reading that would trigger the off cycle. This pattern is distinct from a room that has not yet reached temperature, because in this scenario the room is clearly cooler than the setpoint but the system has not responded by cycling off.
Won't Turn Off With the Remote
A Daikin AC that does not respond to the off command from the remote but does stop when the manual button on the unit is pressed has a remote or signal issue rather than a control board fault. Replace the remote batteries and test again. If the unit responds to the remote after a battery change, the batteries were the cause. If neither the remote nor the manual button stops the unit, the control board is not processing the off command and requires a technician.
Restarts Automatically After Being Turned Off
A Daikin system that turns itself back on after being switched off has either an active timer set to restart at a specific time, or a control board fault that is triggering an automatic restart. Check the remote for any active on timer first. If no timer is active and the unit restarts within a short period of being switched off without any remote command, the control board has a fault that requires a certified Daikin technician to diagnose.
Indoor Unit Not Turning Off But Outdoor Unit Is Off
When the Daikin indoor unit continues running the fan but the outdoor unit has already stopped, this is the indoor unit running in fan-only mode after the compressor has cycled off. This is normal behaviour in some Daikin models that run the indoor fan briefly after the compressor stops to distribute residual cooling from the evaporator coil. If the fan runs for more than ten minutes after the outdoor unit has stopped, it may be a fan setting rather than a fault.
Won't Turn Off After a Reset
A Daikin AC that resumes continuous running after a full power reset has a persistent fault rather than a temporary stuck state. The most likely cause at this point is a thermistor providing an incorrect high temperature reading that immediately triggers the system to restart into cooling, or a control board logic fault that initialises into a continuous run state. A certified Daikin technician needs to perform a thermistor resistance test and a PCB diagnostic to identify the specific fault.
Running All Night Without Cycling Off
A Daikin AC that runs all night without cycling off when it previously cycled normally may have a thermistor that has drifted over time, a room condition that has changed such as a new heat source being added, or a refrigerant deficiency that is preventing the room from reaching the setpoint overnight. Check whether the room is actually at or below the setpoint. If the room is clearly cold but the system keeps running, a thermistor fault is the most likely cause. If the room is still above the setpoint all night, a performance or room condition issue needs to be addressed.
Why Melbourne Homeowners Trust Our Daikin Technicians to Diagnose Continuous Running Faults
Diagnosing a Daikin AC that will not turn off requires distinguishing between a thermistor reporting an incorrect room temperature, a remote or receiver communication fault, a control board logic issue, and a genuine room condition preventing the setpoint from being reached. Each requires a different repair. Our team works exclusively on Daikin systems and performs thermistor tests and PCB diagnostics across Melbourne every week.
Daikin Only Specialists
Every technician works exclusively on Daikin split, multi-head, and ducted systems and knows every continuous running fault pattern specific to the Daikin control architecture.
Thermistor Testing
We carry out thermistor resistance testing as part of every continuous running diagnosis to confirm or exclude sensor faults before recommending any other repair pathway.
Same-Day Service
Same-day Daikin continuous running repair in Melbourne is available. Contact us early for the best chance of a technician attending the same day.
Written Quotes Always
A written quote is provided after the diagnostic inspection and before any repair work begins. You know the cost before we proceed.
Fault History Access
We retrieve the complete inverter fault history to identify any logged events that contributed to the continuous running behaviour, ensuring the repair addresses the cause.
Daikin Continuous Running Repair and Related Services in Melbourne
Whether your Daikin split system keeps running due to a thermistor fault, a remote or receiver issue, a control board problem, or a room condition that is preventing the setpoint from being reached, our certified technicians across all Melbourne suburbs can diagnose and resolve the fault in a single visit.
Daikin Split System Service Melbourne
Full annual service for all Daikin wall-mounted and multi-head split systems, including thermistor function check, refrigerant pressure test, coil clean, and full thermostat cycling confirmation.
Learn MoreDaikin Ducted System Service Melbourne
Comprehensive servicing for Daikin ducted reverse cycle systems including zone controller check, thermistor test, inverter fault history scan, and full system cycling confirmation across Melbourne.
Learn MoreDaikin AC Repair Melbourne
Certified diagnosis and repair for all Daikin continuous running faults, from thermistor replacement and PCB logic repair to remote receiver replacement and refrigerant performance restoration across Melbourne.
Book a RepairFrequently Asked Questions About Daikin Air Conditioner Not Turning Off
These are the questions Melbourne homeowners ask most often when their Daikin system keeps running or will not respond to off commands.
Daikin AC Not Turning Off, What You Now Know
A Daikin air conditioner not turning off is a fault that sits within a well-defined set of causes. The most important first step is confirming whether the room has actually reached the setpoint temperature, because a system running in a room that is genuinely still warm is doing exactly what it should. Once normal operation has been excluded, the investigation moves to timer settings, remote function, thermistor condition, and control board logic.
The majority of Daikin continuous running complaints that go beyond a timer setting are caused by a thermistor fault, a component that is inexpensive to replace and straightforward for a certified technician to test and confirm. Addressing a thermistor fault early prevents the continuous running from accelerating compressor wear and increasing electricity consumption unnecessarily.
If your Daikin split system or ducted unit keeps running when it should not, and the basic checks described in this guide have not resolved the issue, contact a certified Daikin technician in Melbourne for a same-day thermistor and control board diagnostic.
Is Your Daikin Air Conditioner Not Turning Off in Melbourne? We Can Help
Certified Daikin technicians, same-day availability across all Melbourne suburbs, thermistor testing and PCB diagnostics on every continuous running fault, and written quotes before every repair.
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