BoilerFaultCodesMyson Midas 100 Fault codes & diagnostics
0 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Regular Natural Gas 29.3 kW Discontinued
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Status & diagnostic codes 7 operating states & engineer diagnostics
Not faults — these are normal operating states. Tap to expand.
7 operating states & engineer diagnostics
Not faults — these are normal operating states. Tap to expand.
204 Diagnostic Your boiler's electronic control system is experiencing an internal error that is preventing it from functioning, effectively locking the system for safety. LED 1 Status Your boiler is currently checking that there is enough airflow for it to start up safely; this light should turn off automatically once the system is ready to fire. LED 2 Status Your boiler is struggling to clear air through its internal system effectively enough to safely ignite the burner. LED 3 Status Your boiler is signalling that it is asking the internal air extraction motor to speed up to prepare for ignition. LED 4 Status Your boiler is correctly telling you that it has received a signal from your thermostat and is currently turning on the pump to circulate hot water to your radiators. LED 5 Status Your boiler is correctly indicating that it has received a request to start the pump for your hot water. LED 6 Status Your boiler is currently going through its normal startup process to ignite the burner and get your heating or hot water working.