Sime Meridian HE Fault codes & diagnostics

9 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

Combi Natural Gas 2013-2018 Discontinued

Choose your boiler type

The Meridian HE range comes in 2 types

Pick the one you have. The fault codes, GC numbers and manual differ by type.

The fault code is already on your display

Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →

Each cell = one fault code. Hover to identify.

9 High

Fault codes

Tap any card for details

Locate the filling loop (the silver braided hose) underneath the boiler.
Slowly open the small tap(s) on the filling loop until you hear water entering the system.
Watch the pressure gauge until it reaches between 1.0 and 1.2 bar, then close the tap(s) fully.

Check if other gas appliances, like a cooker, are working to confirm your gas supply is on
Ensure your gas meter has credit if you use a prepay meter
Try resetting the boiler by turning the selector switch to the 'R' position for a few seconds

Check that your gas emergency control valve is in the 'on' position
Verify if other gas appliances in your home, such as a hob, are working correctly
Press the reset button on the boiler control panel