Vaillant fault code F.22
Fault code F.22 on a Vaillant boiler (including HRV) means: System water pressure too high, Defective expansion vessel System filled to too high a pressure. Reset the appliance once. If the code comes back, a part is usually faulty. You can check the water pressure and settings yourself; leave work on gas-carrying parts to a certified gas engineer.
After a safety alert (gas, flue gas, combustion), reset no more than once and call in a certified gas engineer. If you smell gas, call your national gas emergency number or 112 immediately.
Cause
Fault code F.22 on a Vaillant boiler indicates: System water pressure too high, Defective expansion vessel System filled to too high a pressure.
Fixing fault code F.22: step by step
- Read the water pressure on the display or gauge. With the system cold it should be between 1.5 and 2 bar.
- If it is lower, top up to 1.5–2 bar with the filling valve or filling loop, then close the valve again.
- Bleed the radiators with a radiator key, then check the pressure again and top up if needed.
- Reset the appliance once. If the code comes straight back, do not keep resetting it.
- Does the pressure drop again within a few days, or does the code come back? Then there is a leak somewhere (radiator, pipe, pressure relief valve or expansion vessel) or the pressure or flow sensor is faulty.
Applies to
Vaillant HRV, HRV 24.
Click a model for the parts list and exploded view of that appliance.
Fault code F.22 on other Vaillant series
The same code does not mean the same thing on every series. Check the rating plate to see which series you have:
- F.22 on Hrpro, ThermoCompact, CW 3/3, CW 4/3 EXP, VC 254/4-7, VCW 254/4-7: Safety shut-down: water shortage.
- F.22 on Hrpro, ecoCOMPACT, ecoFIT pro, ecoTEC classic, ecoTEC exclusive, ecoTEC plus: Dry-fire protection.
- F.22 on ThermoCompact, CWK 245/3, CWK 245/3 R1, VCW 254/3, VCW 255 E, VCW 255/3: Dry-fire protection (no water in appliance).
- F.22 on hrSOLIDE plus, VHR 24-28/3-5: Boiling dry.
- F.22 on ThermoCompact, VCW 255/2 E: Low water protection active dry-fire protection active.
Matching parts
Vaillant parts are available from Instalpunt; shipping to EU countries from €12.95 (€16.95 for more distant countries), usually 3–5 working days.
Parts per Vaillant-series: ecoTEC plus · ecoTEC pro.
This message does not point directly to one faulty part. These are the parts that most often fit this appliance:
- AWB gasket inspection cover € 8.15
- AWB gasket ltv heat exchanger € 8.15
- AWB gasket fan for e.g. HRV 24 801689 € 8.15
Fix it yourself or call an engineer?
Always consult the manual for your appliance and work safely. If in doubt or if the fault comes back, call in a qualified professional. A question about a part? Write to us at info@instalpunt.nl.
Frequently asked questions
What does Vaillant boiler fault code F.22 mean?
System water pressure too high, Defective expansion vessel System filled to too high a pressure.
How do I fix fault code F.22 on a Vaillant boiler?
First check the cause described above. Then restart the appliance using the reset button. If the message comes back, a part usually needs replacing or the fault needs to be repaired by a qualified professional.
Which parts do I need for Vaillant fault code F.22?
That depends on the exact cause. In the Vaillant parts overview at Instalpunt you will find the current price and stock for each part.
Can I fix fault code F.22 myself?
You can reset the appliance and check things like the water pressure or settings yourself. Work on gas-carrying parts must be left to a certified gas engineer.
All Vaillant boiler faults and codes at a glance →