What does the Vaillant F.24 fault code mean?

Your boiler has shut down because the internal water temperature is heating up much faster than it can be circulated away, usually meaning the water is stuck or the pump is struggling.

How much does it cost to fix Vaillant error code F.24?

Typical repair cost for the Vaillant F.24 fault is £150-£350 including labour.

Can I fix Vaillant fault code F.24 myself?

Check that your boiler pressure is between 1.0 and 1.5 bar on the digital display.

Vaillant F.24 Fault Code: What It Means & How to Fix It

What the manual says

Manufacturer manual

Water shortage, temperature rise too quick. Pump blocked, insufficient pump output, air in appliance, water pressure too low

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 heat inside the boiler builds up too quickly because the heated water isn't moving through your radiators fast enough. The most common reasons are a failing circulation pump, a blockage in the system like sludge or limescale, or air trapped within the pipes.

This issue is more frequent during the first cold spell of autumn when the heating is turned back on after months of inactivity, as pumps can seize and debris can settle.

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

Search the official register →

Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like F.24: no call-out fees, no surprise bills.

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Related fault codes

F.20View →F.22View →F.23View →

All 170 fault codes on the ecoTEC Plus 635

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.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.89 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 has shut down because the internal water temperature is heating up much faster than it can be circulated away, usually meaning the water is stuck or the pump is struggling.

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 635

Related guides you might find useful

Banging / kettling / whistling noise

Radiators cold at the bottom

When to replace your boiler

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