Error E9 224

Safety first:

1) If you smell gas: do not operate the boiler, open windows, leave the property immediately and call the gas emergency number.

2) If you are not comfortable with basic checks, or the boiler shows signs of leaking, smoke, or burning smells, switch the boiler off and call a Gas Safe engineer.

3) Do not remove the boiler casing or attempt internal electrical or gas repairs unless you are a registered engineer.

Initial homeowner checks (safe, non-invasive):

1) Note the exact display: E9 224 and any other codes or lights. Take a photo for the engineer.

2) Try a reset: press the boiler reset button once (follow manufacturer instructions). Wait a few minutes to see if the boiler restarts normally. If it refuses to reset or the same fault returns immediately, stop and call an engineer.

3) Check system pressure on the boiler gauge when cold. Typical pressure is around 1–1.5 bar. Very low pressure can cause circulation problems; very high pressure can indicate other faults. Do not over-pressurise the system.

4) Check external condensate pipe (common cause in winter): locate the plastic condensate drain pipe (usually outside or near a drain) and see if it is frozen or blocked. If frozen, carefully pour warm (not boiling) water along the pipe to thaw it and then insulate it. If blocked by debris, clear the visible section if safe to do so.

5) Check the external flue terminal for obvious blockages (nests, leaves, heavy snow). Do not stick objects into the flue; only clear visible external debris.

6) Listen and observe: when the boiler calls for heat, do you hear the pump running? Do radiators heat up in sequence? If radiators remain cold and the boiler runs, circulation/pump issues are likely.

7) Bleed one or two radiators to remove trapped air that can prevent circulation, then re-check pressure and run the system.

Specific diagnostic and fix steps you can try (non-invasive):

1) Reset procedure: after the boiler cools, attempt one reset. If the boiler runs, monitor for recurrence. If it locks out again after a short period, do not repeatedly reset—record the behavior and call an engineer.

2) Condensate thaw: as above, carefully thaw frozen condensate using warm water and then insulate the pipe. If the condensate trap inside the boiler is suspected blocked, do not attempt to remove internal components—call an engineer.

3) Radiator bleeding and pressure check: bleed radiators to release trapped air, then repressurise the system to the correct cold pressure if low, following the boiler handbook instructions. If pressure will not hold or is very high, switch off the boiler and call a pro.

4) Check for obvious circulation: feel pipes at the boiler flow and return (external to the casing if visible) when the system is running. If flow pipe becomes very hot and return remains cold, circulation is poor and the pump or diverter may be faulty—stop and call an engineer.

5) External flue and ventilation: clear visible obstructions from the flue terminal and ensure any ventilation grilles are unobstructed.

When to call a professional (and why):

1) Call a Gas Safe registered engineer if the fault persists after safe checks (reset, condensate thaw, bleeding, pressure check). The likely causes that require a professional include a faulty pump, stuck pressure relief valve, failed fan, failed high limit thermostat or sensor, limescale-clogged heat exchanger, or a defective PCB.

2) Do not attempt to open the boiler, replace sensors, or work on gas/electrical components yourself. These are regulated and potentially dangerous tasks.

3) If the boiler repeatedly overheats, produces unusual smells, or there is any sign of carbon monoxide (symptoms: nausea, headaches, soot, yellow instead of bright flame), turn it off and call an engineer immediately. Consider installing a CO alarm if you do not have one.

What to provide to the engineer:

1) The exact error code and cause code (E9 224), the make and model, and any recent symptoms or events (frozen condensate, power cuts, changes in water pressure).

2) Photos of the display and any visible pipes or the flue terminal, plus notes of any steps you have already taken (reset attempts, thawing, radiator bleeding).

Final notes:

1) E9 224 is an over-temperature safety lockout. It can sometimes be cleared by simple actions, but repeating lockouts usually mean a component needs professional diagnosis and replacement.

2) Always use a Gas Safe registered engineer for repairs on gas appliances. If your boiler is old and repairs are frequent, discuss replacement options with the engineer during the visit.