Medium
F.80 on Vaillant ecoTEC plus 937

Your boiler has detected a faulty connection or wiring issue with one of its internal temperature sensors.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Interruption or short-circuit of SWT inlet sensor only in conjunction with F.91 - NTC defective, NTC cable defective, defective plug connection at NTC, defective plug connection at APC electronics Plug at sensor has short-circuited to housing, short-circuit in cable harness, sensor defective

From this model's manual
Verified against the Vaillant/Vaillant Ecotec Plus 937 Vui Gb 376 3 5 Isim 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 fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

F.91View →

All 38 fault codes on the ecoTEC plus 937

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

conF.0F.01F.02F.03F.10F.11F.12F.13F.20F.22F.23F.24F.25F.27F.28F.29F.32F.49F.61F.62F.63F.64F.65F.67F.70F.71F.72F.73F.74F.75F.76F.77F.78F.81F.90F.91

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