- Boilers
- Electric water heater
E3
Cointra E3 on TND electric water heater: temperature probe
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
On Cointra TND electric storage water heaters with a digital control panel, E3 indicates a temperature sensor fault; switch the unit off with ON/OFF, unplug it once, and contact Cointra service if E3 returns. Never remove the bottom protective cover or touch the 230 V internal wiring yourself.
Safety first
Stop and check this first
- Never remove the protective cover (item 13) or work on the 230 V / 50 Hz internal components yourself; Cointra declines all responsibility unless genuine parts are fitted by its Technical Assistance Service.
- If the tank is drained using lever 1 on the 8.5 bar hydraulic safety group (item 8), it must be refilled and purged of air by closing hot taps from lowest (bidet) to highest (shower) before switching the power back on, to prevent an E1 dry-heating fault.
Safe checks you can perform
- Confirm that the digital display shows E3 rather than E1 or E4
- Switch off with ON/OFF and unplug the Schuko mains plug once
- Check that at least 25 cm of clearance exists below the protective cover
Leave these tasks to a qualified professional
- Do not attempt this professional task: Descale the 1500 W heating element and inspect the magnesium anode
- Do not attempt this professional task: Test the temperature probe and its harness to the TND digital panel
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.
Descale the 1500 W heating element and inspect the magnesium anode
What they doWhile servicing the TND 50, 80, 100 or 150 unit, the authorised technician removes limescale deposits from the heating element (item 5 in Figure 5) and checks the sacrificial magnesium anode (item 15), replacing it if worn.
They must show youthe condition of the 1500 W heating element and the wear state of the magnesium anode.
In writingthe maintenance report detailing element descaling, magnesium anode replacement if performed, and leak testing.
Test the temperature probe and its harness to the TND digital panel
What they doCointra's Technical Assistance Service (SAT) isolates the 230 V supply, removes the protective cover (item 13), tests the temperature probe and its wiring to the digital control panel (item 4), and fits a genuine Cointra replacement probe if faulty.
They must show youthe resistance test on the removed temperature probe and the stable water temperature reading on the digital display after repair.
In writingthe genuine Cointra part number fitted, the verified temperature reading on the display and the official SAT job reference.
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.
Confirm that the digital display shows E3 rather than E1 or E4
- Who:
- you, viewing only the external digital control panel.
- How:
- check the function display next to the ON/OFF and temperature up/down buttons to confirm the alarm code reads E3, and note your tank model (TND 50, 80, 100 or 150).
- Result that matters:
- verifying that the alarm points to the temperature probe (E3) rather than dry heating (E1) or water overheating (E4).
- If the screen shows E1 or E4 instead of E3:
- follow the guidance for an empty tank or overtemperature condition.
- If E3 stays on the display with the alarm active:
- proceed with a single power reset from the wall socket.
- Evidence to keep:
- clear photo of the digital panel displaying E3 and the model rating label.
Evidence: Cointra TND 50, 80, 100 y 150, termos eléctricos: instrucciones de instalación, uso y conservación
Switch off with ON/OFF and unplug the Schuko mains plug once
- Who:
- you, with dry hands and no tools.
- How:
- press the ON/OFF button (Pulsador ON/OFF) on the control panel, unplug the Schuko mains plug from the 230 V / 50 Hz socket for two minutes, plug it back in and press ON/OFF once to see whether the water temperature reading returns.
- Result that matters:
- checking whether the digital control restores the internal water temperature display (with the flashing heating dot) or repeats E3.
- If the normal temperature reading returns without an alarm:
- monitor the heating cycle up to your 30 to 75 °C setpoint.
- If E3 returns immediately:
- switch the water heater off and leave it unplugged until the technician arrives.
- Evidence to keep:
- note of whether E3 reappeared immediately after reconnecting the Schuko plug.
Evidence: Cointra TND 50, 80, 100 y 150, termos eléctricos: instrucciones de instalación, uso y conservación
Check that at least 25 cm of clearance exists below the protective cover
- Who:
- you, by visual inspection from outside.
- How:
- make sure there is at least 25 cm of free space between the bottom protective cover (item 13 in Figure 5, next to the blue cold inlet and red hot outlet pipes) and any fixed obstacle, and check for any water dripping from the casing.
- Result that matters:
- ensuring unobstructed access for the Cointra service technician and ruling out visible tank leaks.
- If the area below the cover is dry and clear:
- let Cointra's Technical Assistance Service know when booking the visit.
- If obstacles block the bottom cover or water is leaking:
- clear the space and keep the heater disconnected from the mains.
- Evidence to keep:
- photo of the lower clearance and dielectric couplings under the water heater.
Evidence: Cointra TND 50, 80, 100 y 150, termos eléctricos: instrucciones de instalación, uso y conservación
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
- Cointra
- Product type
- Electric water heater
Known code variants
- 3 flashes
- 3 parpadeos
- Bongo D series brake failure
- Bongo D30 E3
- Bongo E3
- Bongo scooter error E3
- Bongo serie D fallo del freno
- Cecofry E3 code
- Cecotec Bongo brake error
- Cecotec Bongo error freno
- Cecotec scooter error E3
- Código de error E3
- Código E3 Cecofry
- código E3 Mabe Kraken
- Cointra E3
- Cointra E3 fault
- Cointra electric water heater E3
- Cointra TND E3
- Cosori E3
- E 3
- E-3
- E03
- E3
- E3 appliance overheating
- E3 cesta derecha
- E3 on display
- E3 right basket sensor
- E3 sobrecalentamiento
- Electrolux ELAC309W E3
- Electrolux washer E3
- Electrolux washing machine error E3
- Error 03
- Error 3
- Error Code E3
- error code E3 Mabe Kraken
- Error E3
- error E3 lavadora Mabe
- error E3 lavarropas Electrolux
- error E3 lavavajillas Fagor
- error E3 lavavajillas Smeg
- error E3 termo Cointra
- Fagor 3LVF-623.1 E3
- Fagor 4LVF-639ADX E3
- Fagor dishwasher E3
- Fagor dishwasher error E3
- Fagor dishwasher not heating water E3
- Fagor lavavajillas E3
- falla E3 lavadora Electrolux
- falla E3 Mabe sensor Hall
- Hoover E03
- Hoover E3
- Hoover washing machine E03
- Hoover washing machine E3
- lavadora Hoover E03
- lavadora Hoover E3
- lavadora Mabe E3 no gira
- lavavajillas Fagor no calienta el agua E3
- lavavajillas Smeg no calienta el agua E3
- Mabe E3
- Mabe E3 error
- Mabe E3 motor Hall sensor
- Mabe washer E3
- Mabe washing machine E3
- Overheat protection has activated
- patinete Bongo error E3
- patinete Cecotec error E3
- Protección contra el sobrecalentamiento activada
- Smeg dishwasher E3
- Smeg dishwasher error E3
- Smeg dishwasher not heating water E3
- Smeg lavavajillas E3
- Smeg LVFABCR3 E3
- termo eléctrico Cointra E3
- TND 100 E3
- TND 150 E3
- TND 50 E3
- TND 80 E3
What it means
In the official installation, use and maintenance manual for the Cointra TND 50, TND 80, TND 100 and TND 150 electric water heaters (Section 2.4, Fault Codes, in Spanish and Portuguese), the digital control panel sounds an alarm and displays E3 when it detects a temperature probe failure (Fallo de la sonda de temperatura), distinct from E1 (dry heating) and E4 (water overheating). Other Cointra water heater ranges may use different fault displays. On its own, code E3 never proves that the sensor itself has failed, as a loose harness plug or heavy scale around the probe pocket can also disrupt readings.
Warnings and stop conditions
- Higheditorial warning
Never remove the protective cover (item 13) or work on the 230 V / 50 Hz internal components yourself; Cointra declines all responsibility unless genuine parts are fitted by its Technical Assistance Service.
Evidence: Cointra TND 50, 80, 100 y 150, termos eléctricos: instrucciones de instalación, uso y conservación
- Mediumeditorial warning
If the tank is drained using lever 1 on the 8.5 bar hydraulic safety group (item 8), it must be refilled and purged of air by closing hot taps from lowest (bidet) to highest (shower) before switching the power back on, to prevent an E1 dry-heating fault.
Evidence: Cointra TND 50, 80, 100 y 150, termos eléctricos: instrucciones de instalación, uso y conservación
Symptoms and causes
Probable causes · in order
- Open circuit, short circuit or out-of-range temperature probe readingCommon
Cointra's fault code table for the TND digital panel directly attributes E3 to a fault in the temperature sensor that monitors water between 30 and 75 °C.
Evidence: Cointra TND 50, 80, 100 y 150, termos eléctricos: instrucciones de instalación, uso y conservación
- Loose or oxidised wiring connection between the probe and the digital panelPossible
The TND electrical diagram (Figure 4) links the internal temperature probe to the front digital control panel (item 4), so a poor connection under the protective cover triggers E3.
Evidence: Cointra TND 50, 80, 100 y 150, termos eléctricos: instrucciones de instalación, uso y conservación
- Heavy limescale build-up around the heating element and sensor areaLess common
Section 1.9 notes that limescale accumulates on the heating element assembly (item 5) in hard-water areas and requires periodic removal by the Technical Assistance Service.
Evidence: Cointra TND 50, 80, 100 y 150, termos eléctricos: instrucciones de instalación, uso y conservación
Virtual technician
Does E3 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
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