Error D.14

Safety precautions:

- If you are not competent with boilers, electrics or plumbing, stop and call a qualified engineer. Boilers contain live electrical parts and gas; incorrect work is dangerous.

- Before touching any internal components: switch the boiler off at the power isolate and, if you must access parts, isolate the boiler from the mains. Do not work on gas or electrics unless you are fully trained and qualified.

Initial homeowner checks you can safely do:

1. Note the code and behavior: take a photo of the display and record when the fault appeared and any other codes shown.

2. Try a single reset: press the boiler reset button once and observe. If the code returns immediately or within a short time, further checks are needed.

3. Check system pressure: use the boiler controls to view pressure. If it is below the recommended level (typically around 1.0–1.5 bar on many systems), top up the system using the filling loop according to your manual. Low pressure can affect pump operation. If you are unsure how to top up, stop and call an engineer.

4. Check that heating system service/isolating valves are open: look for T-handles on the flow and return service valves and ensure they are aligned with the pipe (open). If the pump has an isolation lever or valve, ensure it is also open.

5. Listen at the boiler: with the heating calling, listen for the pump running. You may hear a hum or see vibration. If the pump is silent when it should be running, that is a sign of a pump fault or electrical issue.

6. Bleed radiators: bleed a few radiators to remove airlocks, particularly at high points in the system. Air can prevent flow and make the pump appear to underperform.

Specific diagnostic and fix steps (competent DIYer only; otherwise call a pro):

7. After isolating mains power, visually inspect around the pump for signs of water ingress, corrosion, or loose connectors. Do not open electrical connectors while mains is live.

8. If you are comfortable and it is safe to do so, with power isolated you can try to turn the pump shaft very gently by hand (some pump models permit this using a screwdriver in the rotor slot) to check for a seized rotor. If it rotates freely, the mechanical side is less likely to be seized. If it won’t move, the pump is probably seized or blocked and needs replacement.

9. If wiring looks obviously damaged or wet, do not attempt repair yourself. Note this and advise the engineer. A wiring fault between the pump and PCB or a failed connector can produce speed/target errors.

10. Check for blockages or closed valves in the local pipework and any fitted strainers/filters. If you suspect heavy debris or sludge, do not attempt aggressive cleaning yourself — this is typically a job for a heating engineer who may power-flush the system.

When to call a professional:

- If the D.14 error persists after basic checks (reset, pressure top-up, valves open, bleed radiators) call a qualified Gas Safe heating engineer. They will have the tools to test pump current/speed, measure control signals, check the PCB and eBUS/coding settings, and replace the pump or control parts if needed.

- Call an engineer immediately if you notice water leaks, visible electrical damage, persistent boiler lockouts, or if you’re unsure about any step.

Important reminder: Do not attempt gas or mains electrical repairs yourself. Replacing pumps, testing PCB control outputs, or adjusting internal boiler parameters must be done by a trained and certificated engineer. Provide the engineer with the exact code D.14, the actions you have taken, and any other fault codes observed to speed diagnosis.