- Boilers
- Gas boiler
F37
Cointra F37 on a gas boiler: incorrect water pressure
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
Cointra F37 means the system water pressure is incorrect. With the boiler cold, read the gauge: it should show about 1 bar. If it is below 0.8 bar, top up with the filling key and always close it afterwards.
Safety first
Stop and check this first
- If you smell gas, do not reset: do not touch switches or light flames, open windows, close the gas valve if it is within reach, leave and call your distributor's emergency number from outside. Cointra says to disconnect the boiler when it fails and have it repaired only by an authorised technician.
- Top up only with the external filling key and always close it afterwards. If you have to top up often, stop: there is a leak a technician must find.
Safe checks you can perform
- Gauge pressure when cold
- Top up with the filling key
- Visible leaks
- Pressure switch check and leak search by the technician
Leave these tasks to a qualified professional
- Do not attempt this professional task: Pressure drop test
- Do not attempt this professional task: Water pressure switch check
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.
Pressure drop test
What they doThe technician checks with the system at rest whether pressure falls and finds the leak.
They must show youthe pressure at the start and end of the test.
In writingwhere the leak was and what was repaired.
Water pressure switch check
What they doThe technician checks the water pressure switch's connection and operation.
They must show youthe actual pressure against the switch's response.
In writingthe part number of any replaced switch and why.
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.
Gauge pressure when cold
- Who:
- you.
- How:
- with the system cold, read the boiler's gauge. Cointra asks for about 1 bar and to restore it if it drops below 0.8 bar.
- Result that matters:
- whether pressure is below 0.8 bar.
- If it is low:
- top up as the next check describes.
- If it is fine and F37 stays:
- do not top up; it points to the pressure switch, call the technician.
- Evidence to keep:
- a photo of the gauge with the date.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
Top up with the filling key
- Who:
- you.
- How:
- pull out the filling key and turn it anticlockwise to bring pressure back to the starting value, as Cointra describes. Always close the key afterwards.
- Result that matters:
- whether pressure rises and F37 clears.
- If it clears:
- the boiler runs a 300 second air purge shown as Fh; note the date.
- If pressure does not rise or soon drops again:
- stop and call the technician.
- Evidence to keep:
- photos of the gauge before and after and the date of each top up.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
Visible leaks
- Who:
- you.
- How:
- look under the boiler, radiators and valves for water or drips, without taking anything apart.
- Result that matters:
- whether there is a visible leak.
- If you see water or drips:
- there is a leak; do not keep topping up and call the technician.
- If everything is dry and pressure holds:
- it was a one off low pressure.
- Evidence to keep:
- photos of stains or drips.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
Pressure switch check and leak search by the technician
- Who:
- authorised technician.
- How:
- looks for the water leak and checks the water pressure switch and its connection.
- Result that matters:
- whether there is a leak or the switch has failed.
- If a leak is found:
- it is repaired and pressure stops dropping.
- If there is no leak and F37 stays with correct pressure:
- that confirms the switch.
- Evidence to keep:
- a report of what was checked and any part replaced.
Cointra reserves repairs and component replacement for authorised technicians: gas, electrode, valve and ducts are not the user's job.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
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
- Gas boiler
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 Superlative Plus, F37 is incorrect system water pressure. Cointra explains that if pressure drops below the minimum, the boiler shuts down and shows F37; with the system cold pressure should be about 1 bar. The fault table gives two causes: pressure too low, solved by filling the system, or the water pressure switch disconnected or faulty. The code does not tell genuinely low pressure from a switch that reads wrong.
Warnings and stop conditions
- Criticaleditorial warning
If you smell gas, do not reset: do not touch switches or light flames, open windows, close the gas valve if it is within reach, leave and call your distributor's emergency number from outside. Cointra says to disconnect the boiler when it fails and have it repaired only by an authorised technician.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
- Mediumsource verified
Top up only with the external filling key and always close it afterwards. If you have to top up often, stop: there is a leak a technician must find.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
Symptoms and causes
Probable causes · in order
- Pressure too lowCommon
Cointra says to fill the system. If the gauge shows under 0.8 bar cold, this is the cause; if it holds after topping up, there is no fault.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
- Water leakPossible
If pressure falls again soon after topping up, water is escaping somewhere in the system or the boiler.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
- Water pressure switch disconnected or faultyPossible
Cointra lists it as the second cause. It fits if the gauge reads correctly and F37 stays.
Evidence: Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
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
Cointra SUPERLATIVE PLUS 24 C, instrucciones de uso, instalación y mantenimiento
Cointra · 2017 · manual
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