What does the Vaillant F.89 fault code mean?

Your boiler's main internal pump is not speaking correctly to the control board, preventing the system from circulating heat.

How much does it cost to fix Vaillant error code F.89?

Typical repair cost for the Vaillant F.89 fault is £180-450 including labour.

Vaillant F.89 Fault Code: What It Means & How to Fix It

What the manual says

Manufacturer manual

Incorrectpumpdetected: Unsuitablepumpconnected,PWMplugnotpluggedinorhascome loose,multipleplugonthePCBnotpluggedincorrectly,interruptionin cableharness,electronicsdefective

Shared across the range

This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.

What causes this fault?

This fault occurs when the boiler's brain loses communication with the internal pump that pushes hot water around your radiators. It is usually caused by a loose electrical connection, a damaged wiring harness, or the pump itself failing to send the correct signal back to the control board. Without this two-way communication, the boiler shuts down as a safety precaution to prevent overheating.

This fault is more common in autumn when heating systems are turned on for the first time after summer, as pump components can seize or electrical contacts can fail during long periods of inactivity.

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.

Find a Gas Safe engineer

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Related fault codes

F.75View →F.27View →

All 170 fault codes on the ecoTEC Plus 620

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

con d.00 D.000 d.01 d.02 d.04 d.05 d.06 d.07 d.08 d.09 d.10 d.11 d.13 d.14 d.15 d.16 d.17 d.18 d.19 d.20 d.21 d.22 d.23 d.24 d.25 d.27 d.28 d.31 d.33 d.34 d.35 d.36 d.39 d.40 d.41 d.43 d.45 d.47 d.50 d.51 d.58 d.60 d.61 d.62 d.64 d.65 d.66 d.67 d.68 d.69 d.70 F.00 F.0 F.01 F.1 F.10 F.11 F.12 F.13 F.20 F.22 F.23 F.24 F.25 F.27 F.28 F.29 F.32 F.33 F.49 F.61 F.62 F.63 F.64 F.65 F.67 F.68 F.70 F.71 F.72 F.73 F.74 F.75 F.76 F.77 F.78 F.83 F.84 F.85 F.86 F.87 F.88 F.91 F.92 F.97 F22 F70 P.00 P.0 P.01 P.1 P.02 P.2 P.3 P.4 P.5 P.06 P.6 P.07 S.0 S.01 S.1 S.02 S.2 S.03 S.3 S.04 S.4 S.05 S.5 S.06 S.6 S.07 S.7 S.08 S.8 S.10 S.11 S.13 S.14 S.15 S.16 S.17 S.20 S.21 S.22 S.23 S.24 S.25 S.26 S.27 S.28 S.30 S.31 S.32 S.33 S.34 S.36 S.39 S.41 S.42 S.46 S.53 S.54 S.88 S.91 S.96 S.97 S.98 S.99 S.108 S.109 T.02 T.03 T.04 T.05 T.06 T.08

Your boiler's main internal pump is not speaking correctly to the control board, preventing the system from circulating heat.

What the manual says

What causes this fault?

Engineer required

Avoid the next call-out bill

Related fault codes

All 170 fault codes on the ecoTEC Plus 620

Related guides you might find useful

Banging / kettling / whistling noise

Radiators cold at the bottom

Yellow or orange flame — CO safety

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