What Is a Fault Code?

A fault code is a message shown on your heat pump’s controller or display when the system detects a problem. It usually appears as a number and/or letter code (e.g. F.792 or P9) often along with a warning symbol.

Why Would You Check for One?

• To understand why your heat pump has stopped or isn’t working as expected.
• To see if the issue is something simple you can resolve yourself (e.g. by following the Hard Reset, Topping Up Pressure, or Cleaning the Strainer guides).
• To give us accurate information if you need to call for help, a fault code helps us diagnose an issue more quickly.

What To Do if You See a Fault Code

1. Check if the fault clears after following the self-help steps in this guide pack.
2. If the code remains or keeps coming back → make a note or take a photo of the code.
3. Contact us with the details so we can advise on the next steps.

More Detail on Fault Codes

• Each heat pump brand has its own set of fault codes.
• Full fault code explanations are included in the system manuals given to you at handover.
• If you need another copy of the manuals, we can provide these on request.

Where do you Find a Fault Code

Vaillant aroTHERM plus

Controller: sensoCOMFORT

How to Check:

1. Look at the black controller – it may say to contact an engineer – be aware not all faults show on this controller
2. Go to the white controller which will be normally situated in the plant/cylinder location.  It will show if there is an issue and give a fault code with a small description eg. F022 low pressure.
3. Note the code or take a photo.
4. Please note that fault codes begin with F.  Codes beginning with S are operational status codes and generally are not fault codes, take note and if normal operation does not re-establish let us know.  Codes beginning with M require some maintenance, but system may continue to operate.

Mitsubishi Ecodan (FTC 5, 6 or 7 Controllers)

How to Check:

1. The controller will be situated in a central location to the house if being used as a thermostat or in the plant/cylinder. On the main screen, if there’s a fault, a warning or fault code will show.
2. Press any button to light up the screen.
3. Note down the displayed fault code or take a photo.

Grant Aerona R290 Heat Pump

Controller: Grant Smart Controller

How to Check:

1. Faults appear directly on the Smart Controller screen. The controller will either be situated in a central location to the house or in the plant / cylinder location.
2. If a code is active, you’ll see a red exclamation mark in the top left corner of the screen. Press this and it will open a page of all recent fault codes with a code (e.g. E9).
3. Note the code for when you contact support.

Samsung EHS Mono R290 Heat Pump

How to Check:

1. Faults appear on the indoor controller screen (MCU), the controller will either be situated in a central location to the house or in the plant / cylinder location.
2. An error code (e.g. E101, E123) will be displayed if there’s a fault.
3. Note or photograph the code.

When to Call Us (applies to all models)

• If you see a fault code you don’t recognise.
• If the same code reappears after resetting the system.
• If the system shuts down and won’t restart.

Tip: Always take a photo of the fault code and the controller screen – this helps us diagnose the issue faster.