- Boilers
- Tankless gas water heater
F37
Vaillant F.37 on a gas water heater: fan speed deviation
Risk level
High
Professional inspection is recommended.
Urgency
High
Quick answer
F.37 on the Vaillant turboMAG plus warns that the real fan speed does not match the expected speed. The manual blames the wiring, the fan or the circuit board. Try one reset at most and, if it comes back, let a gas technician inspect the heater.
Safety first
Stop and check this first
- If the turboMAG plus shows F.37 and you also smell gas, do not switch lights or appliances on or off, do not smoke or cause sparks, ventilate if you can, shut the gas at the meter, leave the home keeping others out and, once outside, call the emergency services and your gas supplier emergency line.
- Until F.37 is fixed, the fan may not clear the flue gases properly: if a CO alarm goes off or several people get headaches, nausea or dizziness, get into the open air, leave doors and windows open and call the emergency services, because carbon monoxide is invisible and odourless.
Safe checks you can perform
- A single reset as the manual describes
- Listen to the fan without opening
- Fume smell: draught and switch off
- Have the last service date ready
Leave these tasks to a qualified professional
- Do not attempt this professional task: Check safety devices and CO after repair
- Do not attempt this professional task: Trace the fan wiring harness
- Do not attempt this professional task: Decide between fan and board
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.
Check safety devices and CO after repair
What they doThey finish by verifying the safety devices and combustion with test programme D.53, both tasks from the maintenance plan in the installation manual.
They must show youthe heater running without F.37 and the CO measurement.
In writingthe CO value obtained after the repair.
Trace the fan wiring harness
What they doThe gas technician checks the connectors and harness between fan and board and repairs any break before replacing components.
They must show youthe cut or loose point in the harness, or proof it was sound.
In writingthe wiring condition and what was repaired.
Decide between fan and board
What they doIf the wiring is sound, they check whether the fan reaches its speed and, depending on the result, replace either the fan or the printed circuit board.
They must show youthe test that rules one of them out.
In writingthe part replaced and its 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.
A single reset as the manual describes
For error messages, the troubleshooting annex of the user manual suggests opening and closing the hot tap several times, switching the heater off and on and pressing reset. Do it only once; if F.37 shows again, leave it switched off.
Evidence: Vaillant turboMAG plus MAG ..5/1-5 RT, instrucciones de funcionamiento 0020261985_00
Listen to the fan without opening
With the casing closed, notice whether the fan hums, rubs or surges when you draw hot water, or makes no sound at all. Note it for the technician; do not remove the casing, as the manual leaves every repair to a professional.
Evidence: Vaillant turboMAG plus MAG ..5/1-5 RT, instrucciones de funcionamiento 0020261985_00
Fume smell: draught and switch off
If you notice a smell of fumes while F.37 is displayed, create a draught by opening doors and windows, switch the heater off and call an authorised professional, as the user manual asks in its section on flue gas removal.
Evidence: Vaillant turboMAG plus MAG ..5/1-5 RT, instrucciones de funcionamiento 0020261985_00
Have the last service date ready
The manual calls for a yearly inspection and maintenance every two years by an authorised professional. Find the date of the last visit and the data plate details on the left side before requesting the F.37 repair.
Evidence: Vaillant turboMAG plus MAG ..5/1-5 RT, instrucciones de funcionamiento 0020261985_00
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
- Vaillant
- Product type
- Tankless gas water heater
Known code variants
- Alhena Tech C F37
- Anomalía F37 Ferroli
- caldera Lamborghini F37
- Cointra F 37
- Error F37 Cointra
- Error F37 Ferroli
- F-37
- Ferroli error F37
- Ferroli F37
- Ferroli F37 boiler
- Ferroli F37 caldera
- Ferroli F37 presión
- Ferroli F37 pressure
- Lamborghini boiler F37
- Lamborghini Caloreclima F37
- Lamborghini F37
- Lamborghini low water pressure
- Lamborghini presión de agua baja
- Superlative F37
- turboMAG F.37
- turboMAG plus F37
- Vaillant F.37
- Vaillant F37 calentador
What it means
On the turboMAG plus the fan carries the combustion gases out of the appliance. The Annex B table of the installation manual names F.37 a fan speed difference fault and gives it three causes, each with its remedy: a break in the wiring harness (check the harness), a defective fan (replace it) and a defective circuit board (replace the printed circuit board). Unlike F.171, this row does not mention blocked ducts. Even so, a fan that does not turn as it should puts flue gas removal at risk, so the appliance must not be forced.
Warnings and stop conditions
- Criticaleditorial warning
If the turboMAG plus shows F.37 and you also smell gas, do not switch lights or appliances on or off, do not smoke or cause sparks, ventilate if you can, shut the gas at the meter, leave the home keeping others out and, once outside, call the emergency services and your gas supplier emergency line.
Evidence: Vaillant turboMAG plus MAG ..5/1-5 RT, instrucciones de funcionamiento 0020261985_00
- Criticaleditorial warning
Until F.37 is fixed, the fan may not clear the flue gases properly: if a CO alarm goes off or several people get headaches, nausea or dizziness, get into the open air, leave doors and windows open and call the emergency services, because carbon monoxide is invisible and odourless.
Evidence: Vaillant turboMAG plus MAG ..5/1-5 RT, instrucciones de funcionamiento 0020261985_00
Symptoms and causes
Probable causes · in order
- Cut or loose wiring harnessPossible
The table lists a break in the wiring harness first: when the link between board and fan fails, the stated remedy is to check that harness.
Evidence: Vaillant turboMAG plus MAG ..5/1-5 RT, instrucciones de instalación y mantenimiento 0020261986_00
- Fan that cannot reach its speedPossible
A worn or failed fan can stay below the requested speed; if the technician confirms it, the manual says to replace it.
Evidence: Vaillant turboMAG plus MAG ..5/1-5 RT, instrucciones de instalación y mantenimiento 0020261986_00
- Fan control electronicsLess common
With wiring and fan in good order, the remaining cause in the table is the electronic board, and the remedy is to change it.
Evidence: Vaillant turboMAG plus MAG ..5/1-5 RT, instrucciones de instalación y mantenimiento 0020261986_00
Virtual technician
Does F37 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
- 2
Vaillant turboMAG plus MAG ..5/1-5 RT, instrucciones de funcionamiento 0020261985_00
Vaillant · 2018 · manual
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