Myson Wallflame WF IV Fault codes & diagnostics

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

Regular Oil 36.6-44 kW 1970s-1980s Discontinued
Download the Myson Wallflame WF IV manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

The fault code is already on your display

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

Just want the most common Myson Wallflame WF IV faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 3 documented codes

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10

Your boiler's flame is flickering or surging in an unusual, rhythmic pattern, which indicates it is not burning the gas correctly.

Emergency Engineer only £150-300

Parts commonly replaced

  • Gas valve
  • Burner assembly
  • Flue seals
Full explanation for 10
12

Your boiler is failing to burn the fuel correctly, which is allowing the smell of oil to escape into your home.

Emergency Engineer only £150-350

Parts commonly replaced

  • Oil nozzle
  • Flame detector
  • Oil pump seal
  • Flue seals
Full explanation for 12
13

Your boiler is struggling to ignite smoothly, causing small explosions or smoke to escape during start-up, which indicates a serious issue with combustion or venting.

Emergency Engineer only £150-300

Parts commonly replaced

  • Ignition electrode
  • Burner assembly
  • Gas valve
  • Flue seals
Full explanation for 13
Status & diagnostic codes

2 operating states & engineer diagnostics

Not faults — these are normal operating states. Tap to expand.

C551A Diagnostic Your boiler has detected an issue with the sensor that confirms the burner flame is lit, causing it to shut down for safety reasons. R867A Diagnostic Your boiler has detected an issue with the internal electrical connections or a failing control component that is affecting the safe supply of power to its heating system.