BoilerFaultCodesIdeal L 0d Fault Code
Also written as L0D — same fault.
The Ideal L 0d fault code means: your boiler has stopped working because it cannot safely get rid of exhaust fumes or waste water, often due to a blockage or a frozen pipe.. It appears on 3 Ideal models in our database.
Technical description: Condensate pipe blockage / Frozen condensate (appliance makes a gurgling noise prior to locking out)
What causes the Ideal L 0d fault?
This fault occurs when the boiler's sensors detect a blockage that prevents exhaust fumes from leaving the flue or waste water from exiting the condensate pipe. The most common reason is a buildup of debris in the internal trap or an external pipe blockage, causing the system to shut down for your safety. In some cases, a faulty sensor or ignition component may also be incorrectly reporting a blockage.
This fault is significantly more common during freezing winter temperatures, as the external condensate pipe can freeze and cause water to back up into the boiler.
DIY fix possible
Check the white plastic condensate pipe outside for ice and thaw it with warm (not boiling) water.Check that the external flue terminal is not obstructed by debris or snow.Reset the boiler by turning the control knob to 'RE' or pressing the reset button.
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Gas Safe Register →Ideal models that show the L 0d fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal L 0d fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026