- HVAC
- Smart thermostats
SIGNO-EXCLAMACION
Netatmo exclamation point on thermostat: Relay not detected
Risk level
Low
Usually safe to check without specialist tools.
Urgency
Medium
Quick answer
The '!' logo on the Netatmo Smart Thermostat means it cannot detect its Relay, and the app shows 'Thermostat not reachable'. After a Relay restart allow up to 15 minutes; if it stays, fit new AAA batteries and move the thermostat and Relay closer or turn them.
Safety first
Stop and check this first
- Do not open the boiler to check the Relay: any work on its terminals or power supply is done with the power off and by an installer.
Safe checks you can perform
- Wait 15 minutes after an outage or update
- Inspect the batteries and fit three new AAA alkalines
- Move the thermostat and Relay closer or turn them
- Restart the Relay by unplugging it for a minute
Leave these tasks to a qualified professional
- Do not attempt this professional task: Pairing review with Netatmo support
- Do not attempt this professional task: Boiler adapter relocation by an installer
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Pairing review with Netatmo support
What they doIf the logo persists with new batteries and the modules close together, open a case with Netatmo to review the pairing between Relay and thermostat.
They must show youthe thermostat and Relay firmware versions and the connection status logged in the app.
In writingthe case number and whether pairing was redone or a module replaced.
Boiler adapter relocation by an installer
What they doIf the boiler adapter wires need extending to bring the Relay closer, have a heating installer do it with the power off.
They must show youthe boiler terminals used and the new Relay position.
In writingthe length and type of cable added and the final operating test.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Wait 15 minutes after an outage or update
- Who:
- you, in the Netatmo app, without touching anything.
- How:
- think back to any power cut, firmware update or Relay restart and allow up to 15 minutes, the time Netatmo gives for reconnecting and synchronizing.
- Result that matters:
- avoiding needless changes when the alert is only a resync.
- If the '!' clears and the app shows the thermostat again:
- nothing else is needed.
- If the alert is still there after 15 minutes:
- check the thermostat batteries.
- Evidence to keep:
- a screenshot of 'Thermostat not reachable' with the time.
Evidence: A logo appears on the Thermostat screen: what does it mean? · My Thermostat is no longer connected to its Relay. What should I do?
Inspect the batteries and fit three new AAA alkalines
- Who:
- you, opening only the thermostat battery compartment.
- How:
- remove the batteries and look for leaks; clean any oxidation with a cotton swab and white vinegar, then insert brand new, unexpired 1.5V AAA alkaline batteries the right way round.
- Result that matters:
- seeing the 'Searching for Relay' logo and, a few minutes later, the temperatures.
- If the temperatures appear and pressing + and - does not bring back the search logo:
- the link is restored.
- If it searches again or the '!' returns:
- try improving where the modules sit.
- Evidence to keep:
- a photo of the removed batteries and of the screen afterwards.
Evidence: My Thermostat is no longer connected to its Relay. What should I do?
Move the thermostat and Relay closer or turn them
- Who:
- you, moving only the thermostat or the plug-in Relay, never the boiler.
- How:
- shorten the distance between them or change their orientation slightly; Netatmo says to keep them more than 50 cm from other electrical equipment and out of the boiler casing, closed cabinets and metal objects.
- Result that matters:
- getting a steady radio signal between the two modules.
- If the link returns in the new position:
- leave the modules there for good.
- If they cannot see each other even in the same room:
- distance is not the issue and you need help.
- Evidence to keep:
- where they were and where you left them, with photos.
Evidence: My Thermostat is no longer connected to its Relay. What should I do?
Restart the Relay by unplugging it for a minute
- Who:
- you, at the Relay socket or mount.
- How:
- disconnect the Relay from power, wait a minute and reconnect it; its LED should flash 5 times. In a wireless installation, press it firmly onto its boiler adapter so it is fully seated.
- Result that matters:
- forcing a clean reconnection between Relay and thermostat.
- If the LED flashes and the '!' clears within minutes:
- the link is back.
- If the LED does not react:
- the Relay may not be getting power and Netatmo support is needed.
- Evidence to keep:
- a note of what the LED did when you plugged it back in.
Evidence: My heating system doesn't respond to commands from the Thermostat: what should I do?
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- HVAC
- Brand
- Netatmo
- Product type
- Smart thermostats
Known code variants
- logotipo signo de exclamación Netatmo
- Netatmo ! en pantalla
- Netatmo ! logo on screen
- Netatmo termostato desconectado del relé
- Netatmo termostato signo de exclamación
- Netatmo thermostat does not detect Relay
- Netatmo thermostat exclamation point
- Netatmo thermostat lost connection to Relay
- termostato Netatmo no detecta el relé
- Termostato no accesible Netatmo
- Thermostat not reachable Netatmo
What it means
In Netatmo's help article on screen logos, the 'exclamation point' means the Thermostat does not detect the Relay, and the app reports 'Thermostat not reachable'. Netatmo gives three possible causes: synchronization in progress for up to 15 minutes after the Relay restarts (update, power outage), being out of radio range, or the two not being paired. If the thermostat loses power, the screen stays frozen on whatever it last showed. The logo alone never proves that the thermostat or the Relay is faulty, and other models or firmware may vary.
Warnings and stop conditions
- Lowsource verified
Do not open the boiler to check the Relay: any work on its terminals or power supply is done with the power off and by an installer.
Evidence: My heating system doesn't respond to commands from the Thermostat: what should I do?
Symptoms and causes
Probable causes · in order
- Synchronization after a Relay restartCommon
Netatmo says that after an update or a power cut restarts the Relay, reconnecting and synchronizing can take up to 15 minutes.
Evidence: A logo appears on the Thermostat screen: what does it mean? · My Thermostat is no longer connected to its Relay. What should I do?
- Out of radio rangePossible
Thick walls, metal reinforcement or nearby equipment weaken the signal; Netatmo expects an effective indoor range of roughly 10 to 20 metres.
Evidence: My Thermostat is no longer connected to its Relay. What should I do?
- Weak or leaking thermostat batteriesPossible
Netatmo asks you to check the Thermostat power supply first, removing the batteries to look for leaks and fitting fresh, unexpired ones.
Evidence: My Thermostat is no longer connected to its Relay. What should I do?
- Thermostat not paired with the RelayLess common
Among the causes of the logo, Netatmo includes the Thermostat not being paired with the Relay, which moving them closer will not fix.
Evidence: A logo appears on the Thermostat screen: what does it mean?
Virtual technician
Does SIGNO-EXCLAMACION still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
A logo appears on the Thermostat screen: what does it mean?
Netatmo · 2022 · official_doc
- 2
Aparece un logotipo en la pantalla del Termostato: ¿qué es?
Netatmo · 2022 · official_doc
- 3
My Thermostat is no longer connected to its Relay. What should I do?
Netatmo · 2026 · official_doc
- 4
Mi termostato ya no está conectado a su relé. ¿Qué debo hacer?
Netatmo · 2026 · official_doc
- 5
My heating system doesn't respond to commands from the Thermostat: what should I do?
Netatmo · 2026 · official_doc
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