If your Nuos shows a code on the display, note it down first: it helps us diagnose faster. These are the errors we see most often on call-outs. Only one is something you can check yourself; the rest need a technician. For other Ariston appliances, see what to check when an Ariston water heater or boiler shows an error.
The most common errors
| Code | What it means | Usual cause | Can you check it? |
|---|---|---|---|
| 042 | Not enough airflow | Air intake or exhaust blocked, or grilles left on a ducted unit | Yes, see below |
| E2 | Tank water overtemperature | Element heavily scaled | No, call a technician |
| F4 / EMPTY | The unit does not detect water in the tank | Electronic anode fault | No, call a technician |
| 032 | Communication fault between the electronics and the heat pump | Electronics or connections | No, call a technician |
| 335 | Communication fault (equivalent to 032, depending on the model) | Electronics or connections | No, call a technician |
| 021 | Refrigerant gas loss | A leak in the circuit; mainly on Nuos Split models | No, call a technician |
Error 042: what you can check yourself
- Make sure nothing is in front of the air intake and exhaust openings: boxes, clothes or built-up dust.
- If the unit is ducted to the outside, check the factory grilles have not been left on.
- If everything is clear and the error persists, call us.
Dirt built up on the coil: it restricts airflow and performance. It is cleaned during maintenance.
Limescale is behind many breakdowns
E2 is almost always limescale on the element. Water in Alicante and Murcia is very hard and it is the main cause of Nuos breakdowns. With annual maintenance and the unit in GREEN mode, which uses the element very little, problems are very rare. More about heat pump maintenance.
An element removed during an E2 repair: completely coated in limescale.
Important
Do not open the unit or touch the electrical or refrigeration parts: it is dangerous and, if the unit is under warranty, any repair must be done by the official service centre. See how the Nuos warranty works.
Is your Nuos showing an error?
We are the official Ariston service centre in Alicante and Murcia, and we speak English. Tell us the code and the model and we will book you in.
Book a technician Message us on WhatsApp
Frequently asked questions
Can I reset the unit myself?
You can switch it off and on again, but if the code comes back it needs checking. Note down the code before calling us.
Will the warranty cover the repair?
If the unit is under warranty and the fault is not caused by the installation or lack of maintenance, yes. The repair must be done by the official service centre.
