LOW POWER SUPPLY FROM MAINS High

Johnson Starley LOW POWER SUPPLY FROM MAINS Fault Code

Also written as LOWPOWERSUPPLYFROMMAINS — same fault.

The Johnson Starley LOW POWER SUPPLY FROM MAINS fault code means: your boiler is not receiving the correct amount of electricity from your home's power supply to run safely and has shut down as a precaution.. It appears on 1 Johnson Starley model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Check if mains supply to heater is between 190V - 256V @ 50 Hz, check for electrical fault, or replace PCB
Typical repair cost £180-450 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Johnson Starley models that show the LOW POWER SUPPLY FROM MAINS fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Johnson Starley LOW POWER SUPPLY FROM MAINS fault code information on this page is sourced and cross-checked against the official Johnson Starley service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026