BoilerFaultCodesNavien 114 Fault Code
The Navien 114 fault code means: your boiler has detected that the temperature of the exhaust fumes coming out of the flue is too high, so it has safely shut itself down to prevent overheating.. It appears on 1 Navien model in our database.
Technical description: Shutd flue gas thermo: Shutdown due to flue gas thermostat of safety chain
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Avoid the next call-out bill
A cover plan would handle faults like 114: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
Navien models that show the 114 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Navien 114 fault code information on this page is sourced and cross-checked against the official Navien service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026