- Boilers
- Gas boiler
05
Immergas 05 on a gas boiler: flow temperature sensor fault
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
Immergas 05 means the board detects a fault in the flow NTC sensor and the boiler will not start. The table gives no Reset for this code: note when it appeared and, if it persists, call the authorised technical service.
Safety first
Stop and check this first
- If you smell gas: Immergas says to close the meter or main gas tap and, if you can, the boiler's gas tap, open doors and windows, use no naked flames, do not smoke and do not touch switches, sockets, doorbells or phones. Leave the home and call your gas distributor's emergency number from the street.
- Do not open the boiler to check the sensor: Immergas says not to open or tamper with the appliance, and in Stand-by and Off modes it must still be treated as live.
Safe checks you can perform
- Code on the display and boiler status
- Fault list in the information menu
- Flow temperature in the menu
- Sensor and connection check by the technician
Leave these tasks to a qualified professional
- Do not attempt this professional task: Flow NTC sensor measurement
- Do not attempt this professional task: Connector and wiring
- Do not attempt this professional task: Comparison with the safety sensor and fault history
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.
Flow NTC sensor measurement
What they doWith the boiler isolated, the technician measures the resistance of the flow NTC sensor at the current temperature and compares it with the manufacturer's table.
They must show youthe measured value and the temperature at which it was measured.
In writingthe value against the manufacturer's specification and, if replaced, the sensor part reference.
Connector and wiring
What they doThe technician checks the sensor connector and cable, and that the wires sit inside the cable glands with no blackening or burn marks, as Immergas asks at maintenance.
They must show youthe connector and cable checked.
In writingthe defect found and the repair made.
Comparison with the safety sensor and fault history
What they doThe technician compares the flow temperature (d 0.2) with the safety flow sensor reading (d 1.0) and reads the last five faults at d 0.8.
They must show youboth readings and the fault list.
In writingthe readings, the cause found and the operating test after the repair.
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.
Code on the display and boiler status
- Who:
- you.
- How:
- check whether the display flashes the letter E and the number 05 alternately, and whether the boiler provides heating or hot water.
- Result that matters:
- whether the boiler is stopped by E05.
- If E05 stays on and there is no heating or hot water:
- call the technician; the table gives no Reset for this code.
- If it clears by itself and the boiler works:
- note the date and time; an intermittent fault fits.
- Evidence to keep:
- a photo of the display with the code.
Evidence: Immergas Victrix Zeus 25/32, instrucciones y advertencias para instalador, usuario y mantenimiento (1.042022SPA)
Fault list in the information menu
- Who:
- you.
- How:
- press the information button for at least 1 second, step with the same button to d 0.8, which shows the last five faults, and note when E05 appears.
- Result that matters:
- whether E05 repeats and whether it appears with other codes.
- If E05 repeats:
- tell the technician; if it appears with E73 or E74, the safety flow sensor is involved too.
- If it appears once and does not return:
- note the date and time and keep an eye on it.
- Evidence to keep:
- a photo of the fault list and a note of dates and times.
Evidence: Immergas Victrix Zeus 25/32, instrucciones y advertencias para instalador, usuario y mantenimiento (1.042022SPA)
Flow temperature in the menu
- Who:
- you.
- How:
- in the same information menu, step to d 0.2, which Immergas describes as the instantaneous flow temperature leaving the primary heat exchanger.
- Result that matters:
- the value shown, for the technician.
- If a value appears:
- photograph it; the technician will compare it with their measurement.
- If no value appears or the menu does not move on:
- note that too.
- Evidence to keep:
- a photo of the display at d 0.2.
Evidence: Immergas Victrix Zeus 25/32, instrucciones y advertencias para instalador, usuario y mantenimiento (1.042022SPA)
Sensor and connection check by the technician
- Who:
- technician from an authorised company.
- How:
- measures the flow NTC sensor and checks its connector and wiring.
- Result that matters:
- whether the sensor or the connection is at fault.
- If the sensor is outside the manufacturer's specification:
- it is replaced.
- If the sensor is fine and the connector or cable is damaged:
- they are repaired.
- Evidence to keep:
- a job sheet with the measured value and the part replaced.
Immergas reserves maintenance and repairs for an authorised company and tells the user not to open or tamper with the appliance.
Evidence: Immergas Victrix Zeus 25/32, instrucciones y advertencias para instalador, usuario y mantenimiento (1.042022SPA)
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
- Immergas
- Product type
- Gas boiler
Known code variants
- E05
- Error 05 Immergas
- Immergas E05
- Victrix 05
- Victrix E05
What it means
In the Victrix Zeus 25/32 table, E05 is the flow sensor error: the electronic board detects a fault in the NTC sensor on the flow line, the one that measures the water temperature leaving the primary heat exchanger, and the appliance will not start. If the fault persists, Immergas says to call an authorised company. The code does not say whether the sensor, its connector or the wiring is at fault; the technician measures that before replacing any part.
Warnings and stop conditions
- Criticaleditorial warning
If you smell gas: Immergas says to close the meter or main gas tap and, if you can, the boiler's gas tap, open doors and windows, use no naked flames, do not smoke and do not touch switches, sockets, doorbells or phones. Leave the home and call your gas distributor's emergency number from the street.
Evidence: Immergas Victrix Zeus 25/32, instrucciones y advertencias para instalador, usuario y mantenimiento (1.042022SPA)
- Highsource verified
Do not open the boiler to check the sensor: Immergas says not to open or tamper with the appliance, and in Stand-by and Off modes it must still be treated as live.
Evidence: Immergas Victrix Zeus 25/32, instrucciones y advertencias para instalador, usuario y mantenimiento (1.042022SPA)
Symptoms and causes
Probable causes · in order
- Faulty flow NTC sensorPossible
Fits if E05 stays on and the boiler will not start. Immergas places the fault in the NTC sensor on the flow line; the technician measures it before replacing it.
Evidence: Immergas Victrix Zeus 25/32, instrucciones y advertencias para instalador, usuario y mantenimiento (1.042022SPA)
- Sensor connector or wiringPossible
Fits if E05 comes and goes. Immergas asks for the electrical installation to be checked at maintenance for integrity, blackening or burn marks; the code does not tell sensor and connection apart.
Evidence: Immergas Victrix Zeus 25/32, instrucciones y advertencias para instalador, usuario y mantenimiento (1.042022SPA)
Virtual technician
Does 05 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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