Emergency
110E on Navien NCB H

Your boiler is struggling to breathe properly because the pipework that lets out waste gases or takes in fresh air is blocked or damaged.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

What the manual says

Manufacturer manual

Exhaust blockage / Intake air supply exhaust flow err. Exhaust air is blocked due to condensate drain faults, deformed or blocked flue, or exhaust gas entering the air supply pipe.

From this model's manual
Verified against the Navien Ncb H 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 emergency severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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