Model compatibility has not been independently verified
Earlier archive data contained suggested model or series names. Without a clear model/code table in a manufacturer manual, these names are no longer displayed as verified matches.
This is general brand/device guidance; check the model label and official manual.
Open manufacturer sourceWhat does it mean?
The manufacturer identifies F73 as “Water pressure sensor signal too low” for the covered boiler models. Code meanings can differ by model, region and platform; this is not proof that a specific part has failed.
Model match: No manufacturer-manual confirmed exact model list is available for this record. Check the model label and official manual.
Check your exact model manual; the same code can mean something else on other platforms.
The source describes the code; the failed part can only be confirmed by testing the appliance.
Open original manufacturer documentationSafe checks you can try
- 01
Safe check 1
With the boiler cool, record the indicated system pressure and compare it with the model manual.
- 02
Safe check 2
Only top up water if explicitly permitted and described for your exact model.
- 03
Safe check 3
If there is leakage, repeated pressure loss or excessive pressure, stop and request service.
Safety and warranty: Meaning may vary by model. Gas combustion, live electrical work and sealed refrigerant circuits require licensed professionals. If you smell gas, leave the area and call emergency services.
What a technician would check
An authorised technician checks pressure sensor, leaks, circulation pump, expansion vessel and safety devices using the manufacturer procedure.
How to verify the result
After a successful user-level check, normal operation should resume and the code should not return. If it repeats, a qualified technician should inspect the exact model.
Do not dismantle sealed systems, gas valves or electrical control boards. Warranty conditions vary by country and model.
Independent information website, not an authorised service provider.
Manufacturer source
https://www.vaillant.com.tr/pdf/yogusmaliduvartipiisitmacihazlarimontaj65kw-824586.pdfChecked on: 2026-11-10. Manufacturer reference recorded — model-code mapping not independently verified