Grant Euroflame Condensing Fault codes & diagnostics

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

OilRegular Oil 15-35 kW 2005-2015 Discontinued

Replaced by: Vortex

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 Grant Euroflame Condensing faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 4 documented codes

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10

Your boiler is struggling to breathe because the exhaust pipe is likely blocked, causing smoke or fumes to leak out when it attempts to start.

Emergency Engineer only £120-350

Parts commonly replaced

  • Chimney/Flue lining
  • Flue terminal
  • Burner gasket
Full explanation for 10
12

Your boiler is potentially leaking dangerous exhaust gases into your home because a cleaning panel or seal is not fitted correctly.

Emergency Engineer only £90-180

Parts commonly replaced

  • Cleaning cover seal
  • Gasket kit
  • Combustion chamber insulation
Full explanation for 12
Lock-out

Your boiler's safety system has switched the unit off because it is struggling to ignite or is not receiving enough fuel.

High DIY-safe £100-280

What to check first

  1. Check your oil tank level to ensure you haven't run out of fuel.
  2. Inspect the oil supply valves to make sure they are fully open.
  3. Press the illuminated 'Reset' button on the burner once (if it fails to start after two attempts, call a technician).

Parts commonly replaced

  • Fuel filter
  • Photocell
  • Oil pump
  • Nozzle

Related codes

Full explanation for Lock-out
Overheat

Your boiler has become too hot and has automatically shut itself down to prevent damage or safety issues.

High DIY-safe £100-220

What to check first

  1. Allow the boiler to cool down for at least 20 minutes.
  2. Locate the overheat reset button under the black screw cap on the control panel.
  3. Unscrew the cap and firmly press the small reset button until it clicks.
  4. Check that your radiator valves are open and the system pressure is correct.

Parts commonly replaced

  • Overheat Limit Thermostat
  • Circulation Pump
  • Control Thermostat
Full explanation for Overheat