An error code doesn’t automatically mean your heat pump is broken or you’ve got a massive repair bill heading your way. Sometimes it’s something fairly simple.
So, if you’ve got an Ecodan and you’re staring at an L9, U1, E6 or another mysterious code, here’s what it means, what you can safely check yourself and when you need an engineer.
First things first: don’t just keep resetting it
If an error appears, make a note of the code.
You might be tempted to hit reset, and sometimes a reset will clear a temporary fault. But if the same error code keeps coming back, that’s your heat pump telling you there’s an actual problem that needs looking at.
Ecodan L9: Low flow
L9 error code is one you’ll see talked about a lot.
In simple terms, your Ecodan isn’t seeing enough water flowing around the heating system.
There are a few things that can cause it, including:
- Air trapped in the heating circuit
- A blocked strainer or filter
- A circulation pump problem
- A valve not opening properly
- A restriction somewhere in the pipework
- Low or restricted system flow
If you’re comfortable to do so, you can have a look at the basics yourself. Is anything restricting the system that you can remove, or can you see any water leaking from the heat pump? But, don’t start taking the system apart.
If the L9 error code keeps coming back, get an engineer to investigate the problem rather than repeatedly resetting the fault.
E6: Indoor/ Outdoor communication fault
An E6 error code typically occurs following a power cut or similar weather event. This creates a communication fault between the indoor and outdoor parts of the system.
Mitsubishi Electric provides a reset procedure to try if this happens. If this doesn’t fix the issue, this is when your engineer will need to be called.
U1: High pressure
U1 error code is a high-pressure fault which is linked to the outdoor unit.
If you have a U1 code showing on your heat pump, make a note of this and don’t change any of the settings. U1 can be linked to problems with water flow around the system, so an engineer may need to check the system to find the cause of the fault.
If the fault keeps coming back, get an engineer to investigate rather than repeatedly resetting the system.
L3: Water temperature too high
An L3 error code means your Ecodan has detected that the circulation water temperature is too high.
There are a few things that can cause this, including:
- Air trapped in the heating circuit
- A blocked strainer or filter
- A circulation pump problem
- A restriction affecting the flow of water
- A problem elsewhere in the heating system
If you’re comfortable doing so, you can have a look at the basics yourself. Can you see any water leaking from the heat pump, or anything that could be restricting the system? But don’t start taking the system apart.
If the L3 error keeps coming back, get an engineer to investigate the problem rather than repeatedly resetting the fault.
P1: Room temperature sensor fault
A P1 error code means your Ecodan has detected a fault with the room temperature sensor.
The sensor helps your heat pump understand the temperature inside your home so it can control the heating correctly. If there’s a problem with the sensor or its wiring, the system may not be able to read the room temperature properly.
If you’re seeing a P1 code, make a note of the error and try a reset if you’re comfortable doing so.
If the fault doesn’t clear or keeps coming back, you’ll need an engineer to check the sensor, wiring and controls to find the cause of the problem.
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