BoilerFaultCodes
The most common Navien faults
Your boiler has detected that the water pressure inside the heating system is too high for it to operate safely.
Locate a radiator in your home with a bleed valveOpen the valve using a radiator key to release a small amount of water into a clothCheck the boiler pressure gauge until it drops into the green zone (usually between 1.0 and 1.5 bar)Close the radiator bleed valve tightly
Your boiler has detected that the water level inside the heating system is too low to run safely, so it has shut itself down to prevent damage.
Check your boiler's pressure gauge on the front panel.If the needle is below 1 bar, locate the filling loop (usually a silver braided hose under the boiler).Slowly open the valve to let water in until the needle reaches the green zone (typically 1.5 bar), then close it tightly.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Locate the filling loop (usually two silver flexible hoses) underneath the boiler.Open the valves slowly to allow mains cold water into the system.Watch the pressure gauge on the front of the boiler until the needle reaches the green zone (typically 1.0 to 1.5 bar).Close both valves tightly to stop the flow of water.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Locate the external filling loop, which is a flexible silver hose connected to two valves under your boiler.Open both taps on the filling loop slowly to let water into the system while watching the pressure gauge.Close both taps firmly once the needle sits in the green zone, typically between 1.0 and 1.5 bar.
Your boiler's internal communication system is confused because two or more parts are trying to use the same digital identification signal.
Identify all wall-mounted or wireless thermostats connected to your heating system.Check the configuration settings on each thermostat to ensure they are assigned unique zone addresses.Restart the boiler and your thermostat(s) to allow them to re-establish a conflict-free connection.
Your boiler is having trouble 'talking' to its wireless thermostat, meaning it cannot receive signals to turn the heating or hot water on.
Check that your wireless thermostat controller has fresh batteries installedTurn the boiler off at the fused spur for 60 seconds and then turn it back on to reset the connectionEnsure there are no new large metal objects or electronic devices placed between the boiler and the thermostat that could block the signal
Your boiler's computer system has detected a minor internal processing error that is preventing it from operating correctly.
Switch the boiler off at the fused spur or mains power for 60 secondsTurn the power back onUse the control panel to reset the current time and date according to your user manual
Your boiler has detected that the water pressure inside the system has risen too high, causing it to shut down for safety.
Locate the external filling loop, which is a silver braided hose connecting two pipes near the boiler.Ensure both valves on the filling loop are firmly closed to stop more water from entering the system.Bleed one or two radiators in the house to release excess water pressure until the boiler's pressure gauge drops back into the green zone.
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