What does the Viessmann A3 fault code mean?

The boiler has stopped its start-up checks because a sensor in the flue (the pipe that carries exhaust gases outside) is not fitted in the correct position, so a qualified engineer needs to reposition it before the boiler can run safely.

How much does it cost to fix Viessmann error code A3?

Typical repair cost for the Viessmann A3 fault is £80-150 including labour.

Viessmann A3 Fault Code: What It Means & How to Fix It

What the manual says

Manufacturer manual

If the flue gas temperature sensor is not positioned correctly, commissioning is cancelled and fault message A3 is displayed (see page 135).

From this model's manual

Verified against the Viessmann/Viessmann Vitodens 200 W B2ha B2ka 5772909 installation & service manual.

Engineer required

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

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Related fault codes

A2View →F4View →

All 83 fault codes on the Vitodens 200-W B2HA-19

Seeing a different code? Every code this model can display, in one place.

4C 9A 9b 9C 9E 9F 10 18 19 20 28 30 38 40 44 48 50 51 58 59 90 91 92 93 94 98 99 A7 b0 b1 b5 b7 b8 bA bb bC bd bE bF C1 C2 C3 C4 C5 C6 C7 C8 Cd CF d6 d7 d8 dA db dC dd dE dF E0 E1 E3 E4 E5 E7 E8 EA Eb EC Ed EE EF F0 F1 F2 F3 F8 F9 FA FC Fd FE FF

The boiler has stopped its start-up checks because a sensor in the flue (the pipe that carries exhaust gases outside) is not fitted in the correct position, so a qualified engineer needs to reposition it before the boiler can run safely.

What the manual says

Engineer required

Avoid the next call-out bill

Related fault codes

All 83 fault codes on the Vitodens 200-W B2HA-19

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