High
F.01 on Vaillant ecoTEC exclusive 835 VUW 356/5-7

Your boiler has lost the temperature reading from one of its internal sensors, meaning it cannot safely regulate heat and has temporarily shut down.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

NTC plug not plugged in or has come loose, multiple plug on the PCB not plugged in correctly, interruption in cable harness, NTC defective

From this model's manual
Verified against the Vaillant/Vaillant Ecotec Exclusive installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the 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

F.00View →F.02View →F.03View →

All 207 fault codes on the ecoTEC exclusive 835 VUW 356/5-7

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

conF.00F.00F.02F.02F.03F.03F.10F.10F.11F.11F.12F.12F.13F.13F.20F.20F.22F.22F.23F.23F.24F.24F.25F.25F.26F.26F.27F.27F.28F.28F.29F.29F.32F.32F.33F.33F.35F.35F.42F.42F.49F.49F.55F.55F.56F.56F.57F.57F.61F.61F.62F.62F.63F.63F.64F.64F.65F.65F.67F.67F.68F.68F.70F.70F.71F.71F.72F.72F.73F.73F.74F.74F.75F.75F.77F.77F.78F.78F.80F.80F.81F.81F.82F.82F.83F.83F.84F.84F.85F.85F.90F.90F.94F.94P.00P.01P.02P.04P.06P.14S.00S.01S.2S.02S.3S.03S.04S.05S.06S.07S.08S.09S.09S.10S.10S.11S.11S.13S.13S.14S.14S.15S.15S.16S.16S.17S.17S.19S.19S.20S.20S.21S.21S.22S.22S.23S.23S.24S.24S.25S.25S.26S.26S.27S.27S.28S.28S.29S.29S.30S.30S.31S.31S.32S.32S.33S.33S.34S.34S.36S.36S.37S.37S.39S.39S.40S.40S.41S.41S.42S.42S.46S.46S.53S.53S.54S.54S.55S.55S.56S.56S.57S.57S.58S.58S.59S.59S.76S.76S.86S.86S.88S.88S.92S.92S.93S.93S.96S.96S.97S.97S.98S.98S.99S.99

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