F18
FAULT CODE
Glow-worm
Low Water Pressure
Low Severity
DIY Check Possible
System water pressure has dropped below the safe minimum.
Cold Weather Note
Pressure drops are more common in cold weather.
Step-by-Step Fix Guide
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Step 1
Check pressure gauge — should be 1.0-1.5 bar
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Step 2
Repressurise via filling loop
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Step 3
Reset the boiler
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Step 4
Call an engineer if pressure drops repeatedly
Gas Safe Reminder
Work on gas appliances must be carried out by a Gas Safe registered engineer. The steps above cover safe checks a homeowner can perform - any internal component replacement requires a qualified professional. If in doubt, always call an engineer.