Error E9 219

Safety precautions:

- Do not attempt internal electrical or gas repairs unless you are a Gas Safe registered engineer.

- If you smell gas, leave the property immediately and call your gas emergency number.

- Turn the boiler off at the mode selector or the isolator switch if it is in a locked-out state and you are not carrying out the allowed checks.

- Allow the boiler and pipework to cool before touching any pipes.

Initial homeowner checks (safe, easy steps):

1) Reset the boiler once: turn the mode selector to the reset position (flame with a line through it) for about 2 seconds or turn to OFF for 30 seconds, then return to heating. Only reset once or twice. If E9 219 returns immediately, stop trying to reset.

2) Check system pressure on the boiler gauge. It should normally be around 1.0–1.5 bar when cold. If pressure is low (below ~0.8 bar), re-pressurise using the filling loop following the boiler manual. After re-pressurising, try one reset.

3) Make sure radiator valves are open and the room thermostat (and programmer) is calling for heat. Closed valves or a thermostat not calling can stop circulation and cause local overheating.

4) Bleed radiators to remove trapped air which can cause poor circulation and overheating. After bleeding, re-check system pressure and re-pressurise if necessary.

5) Listen and feel: when the boiler attempts to run, listen for the pump (a humming sound) and check whether flow and return pipes to the radiators heat up evenly. If the pump appears dead or pipes are cold while the boiler fires, there may be a circulation fault.

6) Check for visible leaks or recent loss of water pressure and check for frozen external pipework in cold weather. Fixing these (pressure or thawing) and then resetting may clear the lockout.

If initial checks do not clear the fault or E9 219 returns:

- Do not continue to reset. Turn the boiler off and arrange a Gas Safe registered engineer.

What an engineer will check and do (for your information):

- Inspect sensor wiring and connectors for open or short circuits and secure connections. Measure sensor resistance and voltages to confirm if the safety sensor (safety temperature limiter or flow/safety sensor) is faulty.

- Check pump operation and electrical supply to the pump; test for blocked or seized impeller and remove/clear any debris or sludge causing poor circulation.

- Check system circulation: inspect for closed radiator valves, airlocks, or obstruction in the system and flush if required (powerflush or chemical flush by an engineer) to remove sludge/limescale.

- Test the safety temperature limiter and flow/return sensors; replace the faulty sensor or STL if confirmed defective.

- Inspect the heat exchanger for limescale build-up or internal blockage that could cause overheating; if heavily scaled, the heat exchanger may need descaling or replacement.

- Check the boiler control PCB for error history, correct signalling and any evidence of component failure that may cause false sensor readings. Replace PCB only if confirmed faulty.

- Run the boiler and monitor temperatures to confirm fault is cleared and that there is safe, sustained circulation.

When to call a professional immediately:

- If the fault returns after one reset, if the boiler displays the error while running, if you notice leaks, burning smells, or the pump is not running.

- If you are uncomfortable with any of the checks above or if the problem is electrical/wiring, component replacement or involves gas systems.

Final note: E9 219 is a safety shutdown. Basic pressure, thermostat, radiator and bleeding checks are reasonable for a homeowner, but diagnosis and repair of sensors, pump faults, heat exchanger problems or PCB faults must be performed by a Gas Safe registered engineer. Do not repeatedly reset the boiler; arrange professional service if the fault persists.