23 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Keston System 30
This boiler uses LED flash patterns
Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →
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Your boiler has failed to light, so it has safely shut itself down to prevent any buildup of gas.
Your boiler has stopped working because it cannot properly read the temperature of the water flowing through its pipes due to a faulty sensor connection.
Your boiler has stopped working because it has detected that the water pressure inside the system is too low.
Your boiler has stopped working because it cannot detect that the internal fan, which safely clears waste gases outside, is operating correctly.
Your boiler has detected an internal electronic failure and has safely shut down to prevent further issues.
Your boiler has safely shut down because the internal flame went out unexpectedly while it was trying to heat your home.
Your boiler has lost its power supply or the internal fuse has blown, meaning the unit is completely switched off.
Your boiler has automatically shut down because the internal temperature inside the outer casing has become too hot.
Your boiler is currently switched on and ready to work, but it is not starting up because your thermostat or timer is not sending a signal for heat.
Your boiler has lit correctly but the flame has gone out unexpectedly, causing the system to shut down for safety.
Your boiler has detected an internal electronic failure related to the main control board and fan system, causing it to lock out for safety and stop providing heating and hot water.
Your boiler has stopped working because the internal fan is not spinning at the correct speed to safely clear combustion gases.
Your Keston boiler has automatically shut down because the internal water temperature has become dangerously high.
Your boiler has temporarily stopped working because it cannot properly read the temperature of the water flowing through the system.
Your boiler has automatically shut down because the internal temperature around the flue exhaust has become dangerously high.
Your boiler has stopped working because it failed to light the flame, which usually happens if the gas supply is interrupted or there is a temporary ignition glitch.
Your boiler has temporarily shut down because the water inside has gotten too hot, likely due to a temporary blockage in water flow.
Your boiler has automatically shut down because an internal safety fuse has detected excessive heat inside the cabinet.
Your boiler has automatically shut down because the temperature inside the exhaust pipe has become dangerously high.
Your boiler has completely lost its electrical supply and is showing no lights at all on the front display.
Your boiler has temporarily stopped working because it cannot properly read the temperature of the water returning to it.
Your boiler has detected an internal sensor or wiring issue and has safely shut down to prevent any risk.
Your boiler has stopped working because the water pressure inside the system has dropped too low.
BoilerFaultCodes