What does the Viessmann A5 fault code mean?

Your boiler has detected that the internal pump is stuck or there is very little water pressure, preventing it from heating your home.

How much does it cost to fix Viessmann error code A5?

Typical repair cost for the Viessmann A5 fault is £180-350 including labour.

Check the pressure gauge and top it up to 1.5 bar using the filling loop

N/A

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Six most common causes of dropping pressure.

Each noise points to a different fault.

Sludge build-up — needs flushing, not bleeding.