Three Types of Reset on a Mitsubishi System and What Each One Actually Does
The three reset types and what they address
Many homeowners think of resetting an air conditioner the way they think of restarting a phone — turn it off, turn it back on, and hope the problem clears. Mitsubishi systems work differently. Three separate reset types exist, and each one addresses a completely different condition.
The power cycle clears transient faults stored in active memory. The filter indicator reset clears the run-hour counter that triggers the maintenance reminder. The factory reset restores all operating parameters and settings to their original defaults. Using the wrong type achieves nothing for the condition you are trying to address. It may also create a new problem by clearing settings that were correctly configured.
Why the power cycle is not always the right first step
A power cycle is appropriate when a one-off transient fault has occurred and no persistent fault code is present. Many homeowners perform a power cycle as their first response to any problem — including faults that the protection circuit has correctly flagged as requiring attention. Resetting a protection circuit fault without addressing its cause allows the fault condition to continue operating against the component the protection was designed to protect.
The correct first step for any fault code is to write down the exact code shown. Then perform a single power cycle and observe whether the code returns. If the same code reappears after a correctly performed power cycle, the fault is persistent and the cause requires professional attention. Continuing to reset through a persistent fault code progressively removes the protection the code exists to provide.
What a reset cannot fix
No reset type clears a fault whose underlying cause remains active. A fault code caused by a blocked drain returns the moment the system restarts — because the drain is still blocked. A fault caused by low refrigerant returns within seconds of restart because the refrigerant circuit is still below specification. A reset clears the flag, not the condition. This distinction matters because resetting without addressing the cause gives the impression of resolution while the actual fault continues accumulating damage to the affected components.
Which Reset Applies to Your Situation
System not responding to remote
Power cycle reset. Switch off at wall for a full minute and restart.
Filter indicator light is on
Filter indicator reset only. Clean filter first, then use the dedicated reset method for your model.
Fault code showing on display
Record the code, attempt one power cycle. If the code returns, call for service rather than continuing to reset.
Settings or schedule behaving unexpectedly
Factory reset restores all defaults. Only appropriate when settings corruption is confirmed, not as a first response.
System running but not cooling, or water dripping
Do not reset. Switch off and call for service. Resetting does not fix these conditions and risks further damage.
Every Mitsubishi Reset Type Explained With Full Instructions
Follow the instructions for the reset type that matches your situation. Each block explains what the reset does, when to use it, the correct steps for your Mitsubishi model, and what to observe after the reset is complete.
Power Cycle Reset
What This Reset Does
A power cycle clears the active memory of the indoor unit PCB. Transient faults occur during unusual operating conditions — such as a momentary voltage fluctuation or a rapid temperature change — and can activate a fault flag in the active memory without a persistent underlying cause. Cutting power for a sufficient period clears this active flag and allows the system to restart with a clean state.
The power cycle does not clear anything stored in the non-volatile memory of the PCB. Fault codes logged to the PCB fault history, refrigerant pressure readings, and operating hour counters all persist through a power cycle. Only factory-level diagnostic access clears these stored records.
When to Use a Power Cycle
A power cycle is appropriate when the system has displayed a fault code or stopped responding and no obvious physical cause is visible. Perform one power cycle and observe whether the system operates normally afterwards. If the same fault code returns within one operating cycle, the fault is persistent and a service call is the correct next step.
Step-by-Step Instructions
- Switch the system off using the remote control and wait for the indoor unit to complete its shutdown sequence, including any auto-cleaning cycle on models equipped with that feature
- Locate the wall isolator switch for the air conditioning circuit — typically adjacent to the indoor unit or at the switchboard — and switch it to the off position
- Wait a full minute without switching power back on. This duration allows the PCB capacitors to discharge completely, which is necessary for a full active memory clear
- Switch the isolator back on and allow the indoor unit a short period to complete its power-up sequence before attempting to operate it from the remote
- Switch the system on from the remote and observe the display for any returning fault code during the first operating cycle
Filter Indicator Reset
What This Reset Does
The filter indicator on Mitsubishi indoor units activates based on accumulated operating hours rather than actual filter condition. When the hour counter reaches the threshold set for the model, the indicator activates as a reminder to check and clean the filter. The filter indicator reset clears this counter back to zero, restarting the cycle from the point of cleaning.
Resetting the filter indicator without cleaning the filter first restarts the counter while leaving a potentially loaded filter in place. The next reminder will appear at the standard threshold — by which point the filter may carry considerably more contamination than it did at the first reminder. Always clean and fully dry the filter before performing this reset.
When to Use This Reset
Use the filter indicator reset only after the return air filter has been removed, washed correctly, dried completely, and reinserted. On models with a secondary electrostatic filter panel, both the main mesh filter and the secondary panel require cleaning before resetting. The secondary panel has its own separate indicator on applicable models, requiring its own reset as a separate action.
Reset Method by Model Type
The filter indicator reset method varies by model. Most current wall-mounted models include a dedicated Filter button on the remote. Pressing and holding this button while pointing it at the indoor unit receiver will clear the indicator when the reset is accepted. The indicator light extinguishes on successful reset, and some models produce a confirmation beep.
On models without a dedicated Filter button, a different button hold sequence applies — typically involving the Mode button while the system is operating. Floor console models often have a recessed reset button on the unit body rather than the remote. Ducted systems typically use the zone controller menu to navigate to a Maintenance or Filter Reset option.
The exact reset sequence for your specific model is documented in your owner manual. If the manual is not available, the Mitsubishi Electric Australia website provides manuals searchable by model number, which appears on a label inside the front panel of the indoor unit.
Factory Reset
What This Reset Does
A factory reset restores all operating parameters, timer programs, temperature preferences, and operating mode settings to their original manufacturer defaults. This reset is appropriate when the system behaves unexpectedly after a settings change, when a previous occupant has configured the system in a way that cannot be untangled through individual setting adjustments, or when the operating parameters appear corrupted.
A factory reset does not clear the PCB fault history log, the operating hour counters, or the refrigerant circuit calibration data stored in non-volatile memory. These records persist through a factory reset and are accessible only through factory-level diagnostic tools used by licensed technicians.
When to Use a Factory Reset
Use this reset only when settings corruption or misconfiguration is the confirmed cause of the problem. Do not use a factory reset as a first response to any fault code or performance issue. The reset erases all programmed schedules, temperature settings, and custom configurations without warning. Re-entering these settings after the reset requires consulting the original manual for the procedures applicable to your model.
How to Perform a Factory Reset
The factory reset procedure varies across Mitsubishi models and is not accessible through the standard remote control interface on most residential units. Current residential models typically require simultaneous button presses on the remote held for an extended period to enter the advanced settings menu. The exact combination differs by model generation.
The most reliable method is to consult the installation manual for your specific model number rather than applying a generic sequence. The model number appears on a label inside the front panel of the indoor unit. The Mitsubishi Electric Australia website provides installation manuals for current and recent models, searchable by model number.
If the factory reset procedure for your model is not accessible through the owner manual and you are experiencing a settings-related problem, a technician can access the advanced configuration menu during a service visit without requiring a factory reset in most cases.
Situations Where a Reset Helps Versus Situations Where It Does Not
Understanding this distinction prevents the most common reset mistake — repeatedly resetting through a fault that requires professional attention, progressively compounding the damage while waiting for the problem to resolve itself.
A Reset Is Likely to Help
These situations are appropriate for a single reset attempt
A fault code appeared once during an unusual operating event such as a power outage, lightning, or an extreme temperature spike, and has not appeared before
The system stopped responding to remote commands after operating normally for an extended period, with no fault code visible on the display
The filter indicator light is on after the filter has been cleaned, dried completely, and correctly reinserted
The system behaves unexpectedly after a recent settings change, suggesting a configuration rather than a hardware cause
The display shows a code that the fault code reference identifies as a transient protection code rather than a persistent component fault
A Reset Will Not Help
Call for service rather than attempting further resets
The same fault code returns within one operating cycle after a correctly performed power cycle, indicating a persistent underlying cause
Water is dripping from the indoor unit, as the drain blockage or overflow condition that caused the water remains active after any reset
The system is running but not cooling, as refrigerant deficit or coil contamination are not resolved by any reset type
Ice is visible on the connecting pipes, as the restricted airflow or low refrigerant cause of the ice remains after the reset
Any burning smell or electrical odour accompanies the fault, as continuing to power the system risks a more serious electrical failure
The circuit breaker for the air conditioning circuit trips when the system attempts to start
Common Mitsubishi Fault Codes and Whether a Reset Is the Right Response
This table covers the fault codes most frequently reported by Melbourne Mitsubishi homeowners. The reset column indicates whether a single power cycle is a reasonable first response or whether the code requires a service call without attempting a reset first.
| Fault Code | What It Indicates | Reset Response | Action Required |
|---|---|---|---|
| E6 | Communication fault between indoor and outdoor units | One reset only | Perform one power cycle. If E6 returns, the communication wiring or PCB requires professional diagnosis. Do not continue resetting. |
| P1 | Indoor unit room temperature sensor fault | One reset only | Attempt one power cycle. A returning P1 indicates sensor failure or wiring fault requiring component replacement. |
| P4 | Drain overflow detection, float switch activated | Do not reset | Switch off immediately. The drain tray is at or near overflow. Resetting restarts the system and adds more water to a failing drain. Call for same-day service. |
| P6 | Freeze protection, evaporator coil temperature abnormally low | Clean filter first | Switch off, inspect and clean the filter, allow the coil to defrost fully before restarting. If P6 returns with a clean filter, low refrigerant is likely and a service call is required. |
| U1 | High pressure protection, outdoor unit circuit pressure exceeded limit | Do not reset | High pressure codes risk compressor damage if reset and continued. Switch off and call for service. Check outdoor unit clearance before calling. |
| U3 | Discharge temperature protection, compressor outlet too hot | Do not reset | Continuing through a U3 code risks compressor overheating damage. Switch off and call for same-day service. |
| U4 | Communication error between indoor and outdoor units | One reset only | One power cycle is appropriate. A returning U4 requires professional diagnosis of the communication circuit between units. |
| L5 | Outdoor unit overload protection | Do not reset | Indicates electrical overload in the outdoor unit. A power cycle is risky. Call for professional diagnosis before restarting. |
| E1 | Indoor unit PCB fault | One reset only | One power cycle may clear a transient PCB state. A returning E1 requires PCB inspection or replacement by a technician. |
| Filter light only | Run-hour counter has reached the maintenance threshold | Filter reset | Clean the filter correctly, dry fully, reinsert, then use the filter indicator reset method for your model. This is not a fault code. |
Fault code returning after a reset attempt?
Our Melbourne Mitsubishi specialists identify the cause and fix it in a single visit.
Signs That a Reset Is Not the Right Tool for This Fault
A single reset attempt is reasonable for any fault that has not appeared before and shows no obvious physical cause. Beyond that single attempt, continuing to reset through a persistent fault creates a specific risk for each fault type. Understanding when to stop resets and call a specialist protects both the system and your home.
Stop resetting and call us today if any of these apply
- The same fault code has appeared and been reset more than twice without the underlying cause being identified and addressed
- Water is dripping from the indoor unit alongside or after a fault code reset attempt
- The circuit breaker trips when the system restarts after a power cycle
- Any burning smell or unusual odour accompanies the fault, both before and after resetting
- The outdoor fan does not spin when the system restarts after a power cycle
- Ice appears on the pipes after a reset and restart even with a clean filter in place
- The fault code changes to a different code after each reset attempt, suggesting multiple related conditions are developing
Information to have ready when you call
Provide the exact fault code as shown on the display, the model number from the indoor unit label, how many times you have reset the system, whether the code cleared and then returned or never cleared, and any physical symptoms you observed such as ice, water, or unusual sounds. This information allows the technician to identify the most likely cause before arriving and to carry the relevant components for a same-visit resolution.
What Melbourne Homeowners Ask Most About Resetting a Mitsubishi System
Direct answers to the reset questions that come up most often, covering both the technical details and the practical decisions homeowners face when a fault appears.
Yes — but only if done at the wall isolator
Switching off at the wall isolator for a full minute performs a genuine power cycle that clears the active memory of the indoor unit PCB. Switching off at the remote does not achieve this because the PCB remains powered from the wall supply regardless of the remote off command. The system appears off from the remote's perspective but the electronics remain energised.
How long to wait
For a true power cycle, locate the dedicated wall isolator switch adjacent to the indoor unit or in the switchboard and switch it off. Wait a full minute before restoring power. Shorter wait periods may not allow the PCB capacitors to discharge completely, which is necessary for a reliable active memory clear.
The fault has a persistent underlying cause
A fault code that returns consistently after a correctly performed power cycle has a persistent underlying cause that the reset cannot address. The code represents the system's protection circuit identifying a specific condition and preventing continued operation until that condition is resolved. Clearing the code without resolving the cause simply re-exposes the condition and triggers the same code again.
What to do next
Stop resetting and call for a professional diagnostic visit. Have the exact code ready when you call. Each Mitsubishi fault code identifies a specific circuit or component, which allows the technician to focus the diagnostic process precisely rather than starting from a general inspection. Most persistent fault code causes are resolvable in a single visit.
A standard power cycle does not affect the warranty
A standard power cycle reset does not affect the Mitsubishi warranty in any way. The power cycle is a homeowner action explicitly acknowledged in every Mitsubishi owner manual as an appropriate first response to a fault code occurrence. Performing a power cycle is not considered modification of the system and does not create any warranty concern.
Factory reset considerations
A factory reset that alters the operating parameters from the installation configuration is a more complex matter. In most cases, restoring factory defaults on a system with a clean installation configuration does not affect warranty. However, changing the operating parameters from their installed state in a way that is not within the homeowner's scope could be viewed differently. If you are uncertain, contact us before performing a factory reset on a system still within its warranty period.
Turning off via remote is not a reset
Turning the system off using the remote and immediately back on is a power interruption to the operating mode only. The PCB electronics remain continuously powered from the wall supply throughout this process. No active memory is cleared and no fault flags are affected. This action restarts the operating cycle but does not reset anything in the electronic sense.
What a true power cycle achieves
A true power cycle requires cutting the wall supply to the indoor unit for a full minute. This allows the PCB capacitors to discharge and the active memory to clear completely. The system then performs a full power-up sequence on restart, re-establishing all its operating states from the default starting point. This distinction explains why turning the system off and on from the remote has no effect on a fault code, while a wall isolator power cycle sometimes clears a transient fault.
The power cycle principle is the same
Switching off the wall isolator or the dedicated circuit breaker for the ducted system for a full minute and restarting performs the equivalent power cycle to a split system. The key difference is that ducted systems typically have an outdoor unit and an indoor air handler unit connected by a communication link. The wall isolator must cut power to the indoor air handler specifically rather than only to the outdoor unit.
Zone controller restart
Zone controller reset is specific to ducted systems. Some zone controller faults can be cleared through the controller's own restart sequence, which involves switching the controller off at its own power switch rather than at the system's main isolator. If your ducted system has a fault code showing at the zone controller rather than the air handler display, the zone controller restart is the appropriate first step before proceeding to a full system power cycle.
Reset Once if Appropriate Then Call If the Fault Returns
A single power cycle is a reasonable first response to a one-off fault code or an unresponsive system. The filter indicator reset is appropriate after every correct filter clean. The factory reset is appropriate only when settings corruption is the confirmed cause of a problem. No reset type resolves a fault whose underlying cause remains active in the system.
When a fault code returns after a correctly performed reset, the system is communicating a persistent condition that requires professional attention. Our Melbourne team resolves the majority of Mitsubishi fault code causes in a single visit. Call 03 4232 6971 with the exact fault code and a description of what occurred during and after your reset attempt. For the complete fault code reference, see our Mitsubishi error codes guide.