What C7 214 means
C7 214 tells you the boiler asked its fan to start and the fan did not turn. Without the fan there is no air for combustion and no way to clear the flue gases, so the Greenstar stops before it opens the gas valve and shows the code.
Each time a Greenstar fires, the fan runs first to purge the combustion chamber, then the boiler lights. The control box watches the fan speed throughout. In the installation, commissioning and servicing instructions for the Greenstar 9i to 24i System ErP (document 6 720 806 945), Worcester lists cause 214 as "Fan does not run during the start up phase". The instructions for the Greenstar 27i and 30i System Compact (document 6 720 807 726) list C7 214 as a "Fan problem", with "Fan not running" as the possible cause.
In the Compact manual, C7 sits in the locking fault table. Worcester explains that a locking fault flashes the warning triangle and the code on the display, and that manual intervention is needed: once the cause has gone, you press the reset button on the fascia.
C7 214, C7 217 and the C6 fan codes
Several Greenstar codes involve the fan, and the cause code tells the engineer which one they are dealing with.
| Code | Worcester wording | When it happens |
|---|---|---|
| C7 214 | "Fan not running" / "Fan does not run during the start up phase" | At start-up, before ignition |
| C7 217 | "No airflow after a defined period of time" / "Fan has stopped during appliance operation" | During operation |
| C6 215 and C6 216 | Fan running too fast or too slow | Fan turning, but at the wrong speed |
| 214 on the 8000 Life | "Fan shut down during safety time" | During the start-up safety period |
The wording comes from manual tables that copy across in loose columns, so some descriptions are paired with their codes by row order. For C7 217 the Compact manual gives the possible cause as "Fan not running or airflow blocked", which brings the flue into the picture in a way that 214 does not. If your code starts with C6, our page on Worcester C6 215 covers the speed faults.
What causes C7 214
Worcester's System ErP fault table sets out the checks in a clear order, and each one matches a likely cause.
Fan harness or connector
The first check is the fan harness and its connector. A plug that has worked loose, or a wire that has broken inside its sleeving, stops the fan getting power or its control signal.
No 230 V supply to the fan
Worcester tells engineers to measure for 230 Vac across the brown and blue wires to the fan. If there is no voltage, the fault lies upstream at the control box or its connections rather than in the fan.
A failed fan
If the voltage is present and the fan still does not turn, the fan motor itself has failed or seized and needs replacing.
Control box connections or the control box
The last items on the list are the connections at the control box and the control box itself. The Greenstar 8000 Life manual gives a similar sequence for its code 214: reset the appliance, then check the voltage to the fan and the continuity of the fan harness.
Safe checks you can do
- Check the power. Make sure the fused spur is on and nothing else in the house has lost power.
- Make sure the boiler is being asked for heat. Check the thermostat, programmer or app, so you know the boiler is trying to start when you watch it.
- Reset and listen. Press the reset button on the fascia, and listen for the normal whirr of the fan running up before ignition. Silence followed by C7 again is useful to report. Stop after two or three attempts. Our Worcester boiler reset guide shows the button position on each range.
- Look at the flue terminal from outside. If you can see it, note whether anything obvious is covering it. Do not try to clear or touch the flue yourself.
- Note any new noises. Grinding, rattling or humming from the boiler in the days before the fault point towards the fan.
Do not remove the casing or touch the fan, its wiring or the control box. The fan is part of the combustion system and runs at mains voltage. Keep a working carbon monoxide alarm near the boiler, and if you smell gas, call the National Gas Emergency Service on 0800 111 999.
What to tell the engineer
A Gas Safe registered engineer will work through Worcester's checks in order: harness and connector, 230 Vac at the fan, the fan itself, then the control box. After replacing a fan, they should check combustion with a flue gas analyser.
When you book, give them the full code (C7 214, not just C7), the model, whether you heard the fan at all during a reset, any recent power cuts and any noises you noticed beforehand. That information can mean they arrive with the right part.
If you have a Greenstar i System boiler, remember it heats a hot water cylinder. If the cylinder has an immersion heater, you can use it for hot water until the repair is done.
Typical repair costs in the UK
| Job | Typical UK cost |
|---|---|
| Engineer call-out and diagnosis | Typically £60 to £150 |
| Fan harness or connector repair | Typically £100 to £180 |
| Fan replacement | Typically £200 to £400 |
| Control box (PCB) replacement, fitted | Typically £250 to £550 |
| Flue repair, if a C7 217 airflow fault is traced to the flue | Typically £150 to £400 |
Our boiler fan replacement cost guide explains what affects that price, and our Worcester Bosch fault code hub lists the other Greenstar codes we cover.