Low
GREEN LED ON every 0.5-secs on Pro ProCombi 100HE

Your boiler has paused because it has detected a minor temporary issue, likely linked to low water pressure or a small internal communication hiccup.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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.

What the manual says

Manufacturer manual

Temporary fault, e.g.: APS fault, low water pressure

From this model's manual
Verified against the Pro Procombi 100he installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Check the pressure gauge on the front of the boiler; if it is below 1.0 bar, top it up using the filling loop.Turn the boiler off and back on at the fused spur switch to clear the temporary error.Ensure all radiator valves are open and that there are no obvious leaks around the unit.

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