BoilerFaultCodesIdeal 2S01 Fault Code
The Ideal 2S01 fault code means: your boiler is notifying you that it has been configured to be controlled by a single external timer or thermostat wire rather than a smart system.. It appears on 3 Ideal models in our database.
Technical description: 1x Switched Live Mode selected.
What causes the Ideal 2S01 fault?
This code appears because the boiler has been electronically told to look for a single basic control wire to turn the heating on and off. It often happens after a power cut, a system reset, or if a new smart thermostat has been installed incorrectly, causing the boiler's internal settings to mismatch the physical wiring. Rather than a broken part, it is simply the boiler asking for clarification on how it should receive its instructions.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Ideal models that show the 2S01 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal 2S01 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