F22 - Safety switch-off due to low water pressure

What does F22 mean?

The Vaillant Ecotec Plus Boilers have entered a safety mode because they detect low or insufficient water pressure within the system. This is a critical safety measure to prevent damage.

• No or insufficient water in the boiler system.
• Defective water pressure sensor.
• Loose, disconnected, or defective cable to the pump or water pressure sensor.
• Blocked pressure sensor or system blockage (for open vent systems).

Click steps to track your progress.

1. 1

   Check the water pressure gauge on the boiler; if it's low, top up the system water (refer to your boiler's specific instructions).

2. 2

   Ensure the pressure sensor is not blocked by debris or sediment.

3. 3

   Inspect all cables leading to the pump and water pressure sensor for secure connections and damage.

4. 4

   If you have an open vent system, check the resistance on flow and return thermistors and ensure the external pump is spinning.

5. 5

   If everything appears normal, a blockage or a main board issue may be present, requiring a technician.