- Boilers
- Electric water heater
Err 10
Thermor electric water heater Err 10: display link board fault
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
Err 10 (shown on the Water Drop touch interface by the top tip lighting up in red and the bottom base segment in white) means communication is broken between the digital control and the main regulation board. Switch off the heater's circuit breaker for at least 20 seconds to reset it.
Safety first
Stop and check this first
- Perform the 20-second reset exclusively at the household circuit breaker panel: never pry off the front Water Drop touch panel or open the motherboard cover yourself, as live 230 V mains voltage is present inside.
- While Err 10 is active, Thermor keeps the water heater running in degraded mode at a lower water temperature than normal, so you will notice lukewarm or reduced hot water until the link fault is cleared.
Safe checks you can perform
- Verify the red tip and white base light pattern on the Water Drop touch display
- Switch off the water heater circuit breaker at the panel for at least 20 seconds
- Check that mode buttons and normal water temperature return after the reset
Leave these tasks to a qualified professional
- Do not attempt this professional task: Replace the electronic regulation board if Err 10 remains after the breaker reset
- Do not attempt this professional task: Inspect motherboard power supply terminals, sensor plugs and display harness
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.
Replace the electronic regulation board if Err 10 remains after the breaker reset
What they doIf the red top tip and white bottom base remain displayed after isolating power at the circuit breaker for at least 20 seconds, have a qualified technician isolate mains power, open the technical compartment and replace the electronic regulation board.
They must show youthe harness connection between the digital touch interface and main regulation board and the Water Drop display operating without the red top tip after fitting the new board.
In writingthe official part number of the replacement Thermor electronic regulation board and confirmation that degraded mode has cleared.
Inspect motherboard power supply terminals, sensor plugs and display harness
What they doWhile the technical cover is open with power isolated, the technician should verify that the wiring harness linking the main regulation board, temperature probes and front digital touch module is securely seated and undamaged.
They must show youthe internal plug connections between the regulation motherboard and the front touch module before closing the cover.
In writingthe service report covering internal harness inspection, sensor continuity and verified operation across all touch modes.
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.
Verify the red tip and white base light pattern on the Water Drop touch display
- Who:
- you, by looking at the front touch interface without opening the appliance casing.
- How:
- check the segmented Water Drop touch panel (with Absence, Manual, ECO+ and Wi-Fi icons) to confirm that the top tip is lit in red while the bottom base segment is lit in white, and test a hot tap to see if water is still warming in degraded mode.
- Result that matters:
- confirming that the water heater is signalling Err 10, during which Thermor maintains heating in degraded mode at a reduced temperature.
- If the top tip is red and the bottom base is white:
- carry out the 20-second circuit breaker reset at your electrical panel.
- If the top tip is red alongside the two upper-right white segments:
- that light pattern indicates Err 19 (power cut within 24 hours) rather than Err 10.
- Evidence to keep:
- clear photo of the Water Drop touch interface showing the red top tip and white base segment.
Evidence: Mon chauffe-eau affiche une erreur, que faire ? · Comment résoudre un problème de chauffe-eau qui affiche une erreur 10 ou Err 10 ? · Thermor Ceramics Digital Connect y Genius Steatite WiFi, manual de instrucciones 700U08320150
Switch off the water heater circuit breaker at the panel for at least 20 seconds
- Who:
- you, at the household electrical distribution board.
- How:
- turn off the dedicated circuit breaker for the water heater on your electrical panel (or the main switch if the breaker is unmarked), wait at least 20 full seconds with power completely off, and switch the breaker back on.
- Result that matters:
- restarting the main regulation motherboard and re-establishing its communication link with the Water Drop digital touch panel.
- If the red top tip and white base disappear and normal white capacity segments return:
- the reset restored board communication.
- If the red tip and white base come straight back after power returns:
- stop repeating breaker resets and book a technician.
- Evidence to keep:
- photo of the Water Drop display taken one minute after turning the circuit breaker back on.
Evidence: Mon chauffe-eau affiche une erreur, que faire ? · Comment résoudre un problème de chauffe-eau qui affiche une erreur 10 ou Err 10 ? · Thermor Ceramics Digital Connect y Genius Steatite WiFi, manual de instrucciones 700U08320150
Check that mode buttons and normal water temperature return after the reset
- Who:
- you, using the front touch controls or the Cozytouch app.
- How:
- once the red tip clears after the 20-second power cycle, verify that the touch mode buttons (Manual, ECO+ or Absence) and the white shower/water-drop segments respond normally without the top tip turning red again.
- Result that matters:
- confirming that the water heater has exited degraded mode and resumed normal thermostat regulation.
- If all white segments and mode buttons respond normally without red alerts:
- the temporary communication lockup is resolved.
- If the red tip and white base light up again:
- note the model and serial number from the rating label so a professional can replace the electronic board.
- Evidence to keep:
- photo of the appliance rating plate showing model and serial number plus the display status.
Evidence: Mon chauffe-eau affiche une erreur, que faire ? · Comment résoudre un problème de chauffe-eau qui affiche une erreur 10 ou Err 10 ? · Thermor Ceramics Digital Connect y Genius Steatite WiFi, manual de instrucciones 700U08320150
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
- Boilers
- Brand
- Thermor
- Product type
- Electric water heater
Known code variants
- Termo eléctrico Thermor Err 10
- Thermor Ceramics Digital Connect Err 10
- Thermor Duralis Connect Err 10
- Thermor Err 10
- Thermor Erreur 10
- Thermor Malicio 3 Err 10
- Thermor punta gota roja base blanca
- Thermor red drop tip white base
- Thermor water heater Err 10
What it means
Thermor's official page "Comment résoudre un problème de chauffe-eau qui affiche une erreur 10 ou Err 10 ?" and manual 700U08320150 cover Err 10/Erreur 10 on Malicio 3, Duralis Connect, Aéromax Access, Ceramics Digital Connect and Genius Steatite WiFi. The segmented Water Drop touch display has a red top tip and white base: its link to the regulation board reading sensors and powering elements is lost. Heating continues in degraded mode with cooler water. Other models may signal this differently from these touch-display ranges. This code alone does not establish board failure.
Warnings and stop conditions
- Higheditorial warning
Perform the 20-second reset exclusively at the household circuit breaker panel: never pry off the front Water Drop touch panel or open the motherboard cover yourself, as live 230 V mains voltage is present inside.
Evidence: Mon chauffe-eau affiche une erreur, que faire ? · Comment résoudre un problème de chauffe-eau qui affiche une erreur 10 ou Err 10 ? · Thermor Ceramics Digital Connect y Genius Steatite WiFi, manual de instrucciones 700U08320150
- Loweditorial warning
While Err 10 is active, Thermor keeps the water heater running in degraded mode at a lower water temperature than normal, so you will notice lukewarm or reduced hot water until the link fault is cleared.
Evidence: Mon chauffe-eau affiche une erreur, que faire ? · Comment résoudre un problème de chauffe-eau qui affiche une erreur 10 ou Err 10 ? · Thermor Ceramics Digital Connect y Genius Steatite WiFi, manual de instrucciones 700U08320150
Symptoms and causes
Probable causes · in order
- Temporary communication glitch between the touch panel and main regulation boardCommon
A brief electrical disturbance interrupts the data link between the Water Drop touch interface and the main regulation motherboard, placing water heating into degraded mode.
Evidence: Mon chauffe-eau affiche une erreur, que faire ? · Comment résoudre un problème de chauffe-eau qui affiche une erreur 10 ou Err 10 ? · Thermor Ceramics Digital Connect y Genius Steatite WiFi, manual de instrucciones 700U08320150
- Permanent fault on the electronic regulation board or internal interface linkPossible
If the red top tip and white bottom base on the Water Drop display remain lit after switching off mains power for at least 20 seconds, the electronic regulation board must be replaced.
Evidence: Mon chauffe-eau affiche une erreur, que faire ? · Comment résoudre un problème de chauffe-eau qui affiche une erreur 10 ou Err 10 ? · Thermor Ceramics Digital Connect y Genius Steatite WiFi, manual de instrucciones 700U08320150
Virtual technician
Does Err 10 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
Mon chauffe-eau affiche une erreur, que faire ?
Thermor · 2025 · official_doc
- 2
Comment résoudre un problème de chauffe-eau qui affiche une erreur 10 ou Err 10 ?
Thermor · 2026 · official_doc
- 3
Thermor Ceramics Digital Connect y Genius Steatite WiFi, manual de instrucciones 700U08320150
Thermor · 2026 · official_doc
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