Green LED On every 0.5 second Low

Halstead Green LED On every 0.5 second Fault Code

Also written as GREENLEDONEVERY05SECOND — same fault.

The Halstead Green LED On every 0.5 second fault code means: your boiler has paused temporarily and is waiting for conditions to return to normal before it attempts to start again.. It appears on 1 Halstead model in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Temporary fault
Typical repair cost £0-120 (including labour)

DIY fix possible

Check if the water pressure is between 1.0 and 1.5 barEnsure your gas supply is active (e.g., check other gas appliances)Wait 15 minutes to see if the boiler resets itself automatically

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Halstead models that show the Green LED On every 0.5 second fault code

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

Source

Halstead Green LED On every 0.5 second fault code information on this page is sourced and cross-checked against the official Halstead service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026