High
266 on Navien NCM 1130HH

Your boiler has detected that the internal fan responsible for safely clearing exhaust gases is not spinning at the correct speed.

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

266:Fan fault Fan fault: The fan speed differs from its set point by more than ‘LimitFanSpeedError’ % of the actual set point for more than 30 seconds. The error condition disappears if the fan speed is very small or when the set point is changing.

From this model's manual
Verified against the Navien/Navien Ncm 1130hh 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

261View →264View →267View →

All 77 fault codes on the NCM 1130HH

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

96979899100102114116117118121122127157158164187253254257258259260261262263264265267268269270271272273274275276277278280281282283284285286287288289290291292293294295296298299300301302303304305306307308309310311319394395396397

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