Mitsubishi Heavy Industries Code
Mitsubishi E36 Error Code
The Mitsubishi E36 error code comes from Mitsubishi Heavy Industries, not Mitsubishi Electric. On MHI systems it means the temperature of gas leaving the compressor has climbed too high, so the outdoor unit has stopped to protect itself. This guide explains what that means, why it happens and how it gets fixed.
Brand First
Is E36 a Mitsubishi Electric or MHI Code?
E36 belongs to Mitsubishi Heavy Industries, often shortened to MHI. MHI uses a numbered E system for its fault codes. Mitsubishi Electric uses a different system of letter and number pairs, and it does not use E36 with this meaning.
To check your brand, look at the front of the indoor unit and the compliance label on its side. MHI wall splits commonly carry SRK model numbers. Many MHI ducted and packaged systems use RC series wired controllers, which show codes such as E36 on screen. If your badge says Mitsubishi Electric, see our U2 page instead, which covers that maker’s discharge temperature alarm.
On MHI Wall Splits
MHI documentation describes E36 on wall splits as compressor overheat. The compressor has run hotter than its safe limit.
On MHI Packaged and Ducted Systems
On packaged ranges, the manuals describe E36 as high discharge temperature. On larger commercial ranges, it relates to a discharge pipe temperature error, with sub codes for systems with twin compressors.
Plain Words
What Does E36 Actually Mean?
A compressor pumps refrigerant gas and raises its pressure. That process heats the gas. MHI fits a sensor to the pipe leaving the compressor, called the discharge pipe thermistor, to watch that temperature.
When the reading passes its safe limit, the outdoor board stops the compressor and raises E36. It is a protective shutdown. Without it, the compressor oil could break down and the motor windings could suffer heat damage.
Here is the subtle part. E36 usually means the compressor really is running too hot. However, a faulty discharge thermistor or a defective outdoor control board can also produce E36 when the compressor is fine. Part of the technician’s job is to tell those situations apart.
On Your Controller
How Does E36 Appear on an MHI System?
On MHI wired controllers, the code usually appears on the screen when the system stops. Touch screen controllers in the RC-EX range may show a protective stop message along with the code, and the operation lamp may change colour. Older RC-E series controllers display the code and ask you to give it, along with the unit address, to your service provider.
Many MHI controllers also keep an error history with the date and the indoor unit address. That record is very helpful, because E36 often appears on hot afternoons. Try not to clear it before the technician visits.
On SRK wall splits without a wired controller, the indoor unit may signal faults through combinations of the RUN and TIMER lights instead. The pattern for an outdoor protection fault depends on the model, so note what you see and quote your model number when booking.
Causes
What Makes an MHI Compressor Overheat?
MHI documentation points to three broad groups of causes. Here they are, starting with the simplest to check.
Airflow and Heat Rejection
- Clogged indoor filters reducing heat transfer at the indoor coil.
- A dirty outdoor heat exchanger that cannot shed heat.
- Poor clearance around the outdoor unit, so hot discharged air loops back into the intake.
- Leaves, plants or stored items crowding the condenser.
Refrigerant and Control
- Low refrigerant charge, usually from a leak.
- A service valve left closed or partly closed.
- On larger commercial systems, a faulty liquid bypass valve.
- A faulty discharge pipe thermistor or a defective outdoor control board.
Airflow problems are worth ruling out first because they are easy to fix. A compressor working into a blocked outdoor coil on a hot day runs hotter than it should. Refrigerant shortage, though, is the cause technicians find most often on systems that keep tripping.
Safe Steps
What Can I Safely Check for an E36?
E36 needs a technician if it keeps returning. Still, a few homeowner steps are safe and sometimes resolve an airflow related trip.
Stop the System
Press ON and OFF on the controller to stop the unit. Note the code and the unit address shown on screen.Clean the Indoor Filters
Remove and wash the filters, then let them dry completely before refitting. On ducted systems, this is usually the return air filter.Give the Outdoor Unit Space
Clear plants, bins, boxes and debris from around the outdoor unit. Make sure nothing blocks the fan outlet or the coil at the back and sides.Let It Rest
Leave the system off for a while so the compressor cools naturally. Then restart once and watch whether E36 returns.Note the Conditions
Record the outside temperature, time of day and how long the system ran before stopping. This pattern helps the technician.
Do not touch the discharge pipe, which can be very hot, and do not open the outdoor unit. It contains live parts and stored electrical charge. Never attempt to add refrigerant yourself.
The Technician
How Does a Technician Diagnose an MHI E36?
A licensed technician follows a structured sequence to separate true overheating from a sensor or board fault.
- Read the controller error history to see how often and when E36 has appeared.
- Test the discharge pipe thermistor against its expected resistance values.
- Measure the actual discharge pipe temperature during cooling to confirm whether the compressor is genuinely running hot.
- Confirm service valves are fully open.
- Check refrigerant pressures and charge, which requires an ARCtick licence.
- Find and repair any leak before recharging to the correct amount.
- Inspect filters, indoor and outdoor coils, clearances and airflow paths.
- Replace the outdoor control board only if its response is abnormal after other checks.
The order matters. Testing the sensor and measuring real pipe temperature early prevents unnecessary refrigerant work on a system that is not actually overheating.
System Types
Does E36 Differ Between MHI Wall Splits and Ducted Systems?
The idea behind E36 stays constant, yet the practical side changes with the type of system. Knowing which one you have helps set expectations for the visit.
SRK Wall Splits
These pair a single indoor unit with a compact outdoor unit. Diagnosis focuses on the outdoor unit, its clearance and the refrigerant charge. Access is usually simple unless the outdoor unit is mounted high on a wall.
Ducted Systems
MHI ducted systems often have larger outdoor units serving the whole home. They work hard on hot days, so condenser cleanliness and clearance matter a great deal. The indoor unit and return filter are usually in the roof or a hallway.
Multi Splits
Several indoor units share one outdoor unit. An E36 affects every head at once, because the compressor is shared. The technician focuses on the outdoor side first.
Packaged and commercial ranges, often found in shops and offices, follow the same logic with larger compressors. Some have more than one compressor, and their manuals use sub codes to identify which one tripped. If you manage a commercial site, note the full code exactly as it appears, including any number after a dash.
Regardless of type, the first visit usually answers the key question: is the compressor truly running hot, or is a sensor or board giving a false alarm? Everything else follows from that answer.
Prevention
How Can I Reduce the Chance of E36?
Simple habits reduce strain on the outdoor unit and give it more headroom in a heatwave.
- Clean indoor filters monthly during heavy cooling periods.
- Keep the outdoor unit clear of plants, fences, stored items and garden waste.
- Book a professional service with an outdoor coil clean before summer.
- Avoid setting extremely low temperatures on the hottest afternoons.
- Pre cool the home earlier in the day rather than starting at peak heat.
None of these will fix a leak, but they help a healthy system stay well clear of its protection limits.
Keep Running?
Is It Safe to Keep Using an MHI Unit With E36?
A single restart after cleaning filters and clearing the outdoor unit is reasonable. If E36 returns, stop using the system and book a visit.
Repeated overheating trips are hard on the compressor. Each time, the compressor runs hot until protection cuts in. Over weeks, that cycle can shorten compressor life considerably, and the compressor is the most costly part of any system.
If the weather is extreme, use fans and other ways to stay cool while you wait. Look after elderly family members, young children and pets in particular. Protecting the compressor now is better than facing a much larger repair later.
Australian Heat
Why Is E36 So Common in Australian Summers?
E36 is closely tied to heat. On very hot days in Perth, Adelaide and western Sydney, outdoor units work against scorching air. Discharge temperatures rise naturally, and any weakness in the system shows up quickly.
That weakness is often a slow refrigerant leak. A system that is a little short of gas may cope through spring, then trip on E36 during the first serious heatwave. Humid Brisbane summers add load too, keeping compressors running for long periods.
Placement is another factor. Outdoor units squeezed into narrow side passages, tucked under decks or boxed in by screens can recirculate their own hot air. MHI documentation lists poor clearance as a cause for exactly this reason. Coastal salt air in beachside suburbs, including those around Melbourne, also corrodes coils and fins over time, reducing heat rejection and sometimes creating leaks.
Clearance Matters
How Much Space Does an Outdoor Unit Need?
MHI installation manuals specify minimum clearances for each model, and they vary. We will not quote figures here because they depend on your unit. However, the principles are the same for every system.
Air In
The coil draws air through the back and sides. Fences, walls and plants too close to these faces starve the coil of fresh air.
Air Out
The fan pushes hot air out the front. If that air hits a wall or fence and bounces back, the unit breathes its own exhaust and runs hotter.
Above and Around
Shelves, awnings or stored items directly above can trap rising heat. Keep the space around the unit open and tidy.
If your outdoor unit sits in a cramped spot, ask the technician whether clearances meet the manufacturer’s guidance. Sometimes moving a few items is enough. In other cases, relocating the unit may be worth considering.
Related Codes
Which Other Codes Relate to E36?
E36 often sits alongside other MHI protection codes. It also has a close conceptual cousin on Mitsubishi Electric systems.
MHI E57
Refrigeration cycle protection, closely linked to low refrigerant or a closed service valve.
Mitsubishi Electric U2
The other maker’s high discharge temperature alarm, with similar causes.
All Mitsubishi Codes
Browse confirmed codes for both Mitsubishi Electric and MHI.
MHI also lists a separate code, E39, for a fault in the discharge pipe sensor itself on many ranges. For other brands, visit our main error codes library.
Booking
How Do I Arrange an E36 Repair?
Rapid Air Cooling takes your booking and sends an independent licensed technician. We are not a Mitsubishi Heavy Industries dealer and do not claim manufacturer accreditation. Refrigerant work is carried out by ARCtick licensed technicians.
Choose your city. Sydney residents can visit Sydney air conditioner repairs or the Sydney Mitsubishi page. Melbourne residents can use Melbourne repairs. In Brisbane, there is our Brisbane repair page. Perth homes can use Perth repairs and Mitsubishi in Perth, while Adelaide homes can use Adelaide repairs.
Our national Mitsubishi air conditioning page covers both makers. The troubleshooting guides help with symptoms like poor cooling, and you can learn about our air conditioning service Australia wide.
Good to Know
What Extra Details Help With MHI E36?
Open more detail
The meaning of E36 shifts slightly between MHI product families. Wall splits describe it as compressor overheat, packaged systems as high discharge temperature, and larger commercial systems as a discharge pipe temperature error with sub numbers for multiple compressors. The core idea stays the same, but the technician will use the manual for your exact range.
A sensor fault can masquerade as overheating. If the discharge thermistor drifts, it may report a high temperature that is not real. Measuring the actual pipe temperature with a separate instrument quickly reveals whether the sensor is lying.
Some owners notice E36 only in cooling, not heating. That makes sense, because summer heat adds load to the outdoor unit. If you see it in heating as well, mention that, as it may point more strongly towards refrigerant or valve problems.
Closed service valves are mostly an installation issue. After an outdoor unit is fitted or relocated, the installer opens the valves to release refrigerant into the system. If one is left partly closed, the system may run for a while before heat and load expose the restriction. An E36 soon after new installation or relocation is a strong hint to check the valves first.
On the control side, the outdoor board reads the discharge thermistor and decides when to stop the compressor. A board with a failing input can misjudge that reading. Technicians compare the board’s response with the measured sensor value before deciding the board needs replacing, since boards are among the more costly parts.
After a repair involving refrigerant, ask for a record of the work. Knowing when and how much refrigerant was added, and where any leak was found, is valuable if the system ever has problems again.
Questions
Frequently Asked Questions
Is E36 a Mitsubishi Electric code?
No. E36 with this meaning belongs to Mitsubishi Heavy Industries. Mitsubishi Electric uses U2 for its high discharge temperature alarm.
Can a dirty outdoor unit cause E36?
Yes. A dirty outdoor heat exchanger or poor clearance around the unit are listed causes. Clearing the area is a safe first step.
Does E36 always mean low refrigerant?
No. Low refrigerant is common, but a closed valve, airflow problems, a faulty discharge sensor or a defective control board can also cause it.
Why does E36 only appear on very hot days?
High outdoor temperatures push discharge temperatures up. A system with a small weakness, such as a slow leak, may only cross the limit in extreme heat.
Can I keep resetting my MHI unit?
One reset after cleaning filters and clearing the outdoor unit is fine. Repeated resets make a hot compressor work under stress, so book a technician instead.
What should I tell the booking team?
Give the code, the unit address, the model number, and when E36 appears. Mention any recent refrigerant work or relocation.
Is E36 dangerous?
It is not usually a safety hazard for people. It is a protective stop for the compressor. Leave the system off and let a technician investigate.
MHI System Stopping on E36?
Call us with your model number and code history, and we will book a licensed technician to find the cause.
Reviewed by AC repair and service specialist on 22 October 2026. How we write our articles