- Boilers
- Electric water heater
240
Ariston 240 on Lydos Hybrid heater: anode short circuit
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
High
Quick answer
On an Ariston Lydos Hybrid Wi-Fi electric water heater, error code 240 means a short circuit on the impressed current anode and turns off both the heat pump and the electric heating element. Reset once by pressing the ON/OFF key twice; if 240 returns, contact technical assistance.
Safety first
Stop and check this first
- Before accessing any terminals or removing covers on the Lydos Hybrid Wi-Fi, all electrical supply circuits must be disconnected using the external two-pole switch.
- Ariston states that corrosion protection from the titanium impressed current anode is only assured when the water heater remains permanently connected (24 h/24 h) to the mains power supply.
Safe checks you can perform
- Confirm code 240 on the display and the flashing ON/OFF key
- Reset the water heater once by pressing the ON/OFF key twice
- Note whether any recent descaling or flange maintenance was carried out
Leave these tasks to a qualified professional
- Do not attempt this professional task: Professional check of the anode plug on the main board and wiring at the flange
- Do not attempt this professional task: Main electronic board replacement by technical assistance if error 240 returns
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.
Professional check of the anode plug on the main board and wiring at the flange
What they doAfter isolating all power supply circuits via the external two-pole switch, the technician must verify the electrical connection of the impressed current anode (terminal I) on the main board (part O) and inspect the flange connections (black wire on the anode, white wire on ground).
They must show youthe condition of the anode connector on the main board and the black anode wire and white ground wire on the flange.
In writingthe continuity and short-circuit test results for the impressed current anode circuit before any board replacement.
Main electronic board replacement by technical assistance if error 240 returns
What they doIf error 240 reappears after checking the anode wiring and resetting the product by pressing ON/OFF twice, Ariston's troubleshooting table instructs replacing the main board (tarjeta madre) using original spare parts.
They must show youthe replaced main board and the live display confirming code 240 is gone and heating is restored.
In writingthe original Ariston spare part reference fitted and the completed safety and function check.
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 code 240 on the display and the flashing ON/OFF key
- Who:
- you.
- How:
- check the user interface panel (part P) to verify that the ON/OFF key is flashing and the display reads 240, noting that with this fault both the electric heating element and the heat pump are switched OFF.
- Result that matters:
- confirming that hot water production has stopped due to impressed current anode short-circuit code 240.
- If the screen shows 240 with the ON/OFF button flashing:
- record the code and perform the single reset procedure.
- If the screen shows 241 instead of 240:
- 241 indicates an open circuit on the anode (which starts by checking whether the tank is filled with water).
- Evidence to keep:
- clear photo of the control panel showing error code 240.
Evidence: Ariston Lydos Hybrid Wi-Fi, calentador de agua eléctrico híbrido: instrucciones de uso y mantenimiento 420010890100
Reset the water heater once by pressing the ON/OFF key twice
- Who:
- you.
- How:
- follow the action listed in the Lydos Hybrid Wi-Fi error table for code 240: reset the product once by pressing the ON/OFF key twice to switch it off and back on without removing any covers.
- Result that matters:
- checking whether the fault was transient or whether error 240 immediately returns.
- If code 240 clears and stays off:
- monitor the unit to ensure normal heating resumes.
- If error 240 reappears on the display after resetting:
- do not keep pressing ON/OFF (which would trigger lockout code 314) and contact technical assistance.
- Evidence to keep:
- note of whether code 240 returned after pressing the ON/OFF key twice.
Evidence: Ariston Lydos Hybrid Wi-Fi, calentador de agua eléctrico híbrido: instrucciones de uso y mantenimiento 420010890100
Note whether any recent descaling or flange maintenance was carried out
- Who:
- you.
- How:
- check whether error 240 started right after a technician descaled the heating element or inspected the anodes at the bottom flange, so you can share that history with service.
- Result that matters:
- giving the technician helpful context in case the anode wires at the flange were pinched or swapped during reassembly.
- If maintenance was recently performed on the flange or anode:
- mention this when booking the service visit.
- If no recent work was done on the water heater:
- book an authorised Ariston technician to inspect the anode wiring and main board.
- Evidence to keep:
- date and service receipt of any recent maintenance work on the water heater.
Evidence: Ariston Lydos Hybrid Wi-Fi, calentador de agua eléctrico híbrido: instrucciones de uso y mantenimiento 420010890100
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
- Ariston
- Product type
- Electric water heater
Known code variants
- ánodo corriente impresa cortocircuito 240
- Ariston 240
- Ariston 240 impressed current anode short circuit
- Ariston error 240
- Ariston Lydos Hybrid 240
- Ariston water heater error 240
- Error 240 Ariston
- error 240 termo Ariston
- Lydos Hybrid 240
What it means
According to the official Ariston Lydos Hybrid Wi-Fi manual (80 L and 100 L models, doc. 420010890100, published in Spanish and Portuguese), error 240 belongs to the domestic hot water circuit error group and indicates a short circuit on the impressed current anode (Ánodo de corriente impresa: cortocircuito, part P on the general diagram and terminal I on the wiring diagram, alongside sacrificial magnesium anode O). While 240 is active, the ON/OFF button flashes and both the 1200 W heating element and the heat pump stay OFF. Other Ariston models may differ. By itself, code 240 never proves the main board or anode is defective, as shorted leads on the flange cause the same fault.
Warnings and stop conditions
- Higheditorial warning
Before accessing any terminals or removing covers on the Lydos Hybrid Wi-Fi, all electrical supply circuits must be disconnected using the external two-pole switch.
Evidence: Ariston Lydos Hybrid Wi-Fi, calentador de agua eléctrico híbrido: instrucciones de uso y mantenimiento 420010890100
- Mediumeditorial warning
Ariston states that corrosion protection from the titanium impressed current anode is only assured when the water heater remains permanently connected (24 h/24 h) to the mains power supply.
Evidence: Ariston Lydos Hybrid Wi-Fi, calentador de agua eléctrico híbrido: instrucciones de uso y mantenimiento 420010890100
Symptoms and causes
Probable causes · in order
- Short circuit on the titanium impressed current anode wiring or flange terminalsCommon
The black wire connected to the impressed current anode or the white ground wire at the heating element flange is shorted to earth or making unintended contact.
Evidence: Ariston Lydos Hybrid Wi-Fi, calentador de agua eléctrico híbrido: instrucciones de uso y mantenimiento 420010890100
- Damaged or poorly seated anode connector on the main electronic boardPossible
The impressed current anode plug (terminal I on the Fig. 4 wiring diagram) is improperly seated or shorted at its socket on the main board (part G/O).
Evidence: Ariston Lydos Hybrid Wi-Fi, calentador de agua eléctrico híbrido: instrucciones de uso y mantenimiento 420010890100
- Fault on the main electronic board supplying the active anode circuitLess common
Ariston's error table notes that if error 240 reappears after resetting and verifying all component connections to the main board, the main board itself requires replacement.
Evidence: Ariston Lydos Hybrid Wi-Fi, calentador de agua eléctrico híbrido: instrucciones de uso y mantenimiento 420010890100
Virtual technician
Does 240 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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