Warmflow E16 Fault Code: Causes, Fixes & Repair Costs
What does the Warmflow E16 fault code mean?
The E16 code on a Warmflow boiler signals that the control board has detected a problem with the flue fan. The fan's job is to push combustion gases safely out of your home through the flue — without it working correctly, the boiler's electronics will refuse to fire the burner as a precaution. This is a deliberate safety lockout: the boiler shuts itself down rather than risk harmful gases building up inside. Because gas components are involved, diagnosing and fixing E16 is a job for a Gas Safe registered engineer.
General guidance only — not a substitute for professional advice, and not certified by a Gas Safe engineer. Always have your specific appliance assessed by a qualified professional. Any gas work must be carried out by a Gas Safe registered engineer. If you smell gas or suspect carbon monoxide, leave the property and call the National Gas Emergency line on 0800 111 999.
Common causes
- Worn or burnt-out fan motor Common
The fan motor's internal windings can burn out or seize over years of normal use, particularly in older boilers. When the motor fails to spin at the speed the PCB expects, E16 is triggered. This is the most frequent root cause, especially in boilers that are five or more years old.
- Loose or damaged wiring between the fan and PCB Common
Vibration over time can loosen the electrical connectors running from the fan assembly to the circuit board. Damaged insulation or a corroded terminal can disrupt the speed-feedback signal, making the PCB think the fan has failed even when the motor itself is still serviceable.
- Worn or deteriorated fan bearings Sometimes
The bearings that support the fan impeller can wear down or become contaminated with debris. Deteriorated bearings cause the fan to run erratically or seize entirely, both of which the PCB will register as a fault.
- Faulty PCB Rare
If the circuit board itself is misreading the fan's speed signal — or has developed an internal fault on the fan-monitoring circuit — it can generate a false E16 even when the fan is mechanically sound. This is a less common but more costly scenario; a Gas Safe engineer will rule out all other causes before condemning the PCB.
How to fix it
- Check that your gas supply is on DIY safe
Confirm other gas appliances in your home (such as a hob or gas fire) are working normally. If they are not, contact your gas supplier rather than continuing to reset the boiler.
- Attempt a boiler reset — up to twice DIY safe
Locate the reset button or reset procedure described in your Warmflow user guide and follow it. An occasional one-off glitch can sometimes be cleared this way. If E16 returns immediately or after a short time, do not keep resetting — repeated resets will not fix a genuine fan fault and can mask the underlying problem.
- A Gas Safe engineer should inspect the fan assembly Gas Safe engineer
The engineer will check that the fan spins freely, measure whether it reaches the correct speed, and look for any physical damage to the impeller or housing. They will also try adjusting fan speed parameters through the boiler's diagnostics before moving to component replacement.
- A Gas Safe engineer should check all associated wiring and connectors Gas Safe engineer
The wiring loom between the fan and the PCB will be inspected for loose terminals, corrosion, or damaged insulation. In many cases, repairing or replacing the wiring alone is enough to clear the fault at a lower cost than a full fan replacement.
- Fan replacement if the motor or bearings have failed Gas Safe engineer
If the fan unit is worn out or seized, the engineer will fit a replacement. For older Warmflow boilers, a complete fan assembly replacement is usually preferable to attempting a motor rebuild, as a repaired old unit is unlikely to last much longer.
- PCB inspection and replacement as a last resort Gas Safe engineer
Only after ruling out the fan, bearings, and all wiring will the engineer consider the PCB. A replacement PCB is expensive; if the boiler is already ageing and the repair cost is approaching that of a new unit, the engineer should advise you honestly on whether replacement makes more financial sense.
- Call a Gas Safe registered engineer if you have not already done so Gas Safe engineer
E16 requires professional diagnosis. Contact a Gas Safe registered engineer (verify registration at gassaferegister.co.uk) who has experience with Warmflow boilers. Warmflow also operates a service line that can direct you to an approved engineer.
Parts you may need
- Warmflow flue fan assembly · from £120
- Fan wiring loom / connector harness · from £25
- PCB (printed circuit board) · from £280
The exact spare depends on your boiler's GC number (on the data badge). Check this against the part before buying.
Typical repair cost
Expect to pay roughly £200–£380, depending on the underlying cause.
Frequently asked questions
Can I fix a Warmflow E16 fault myself?
No. While you can safely check your gas supply is on and attempt a reset once or twice, the fan assembly, its wiring, and the PCB are all components that must be worked on by a Gas Safe registered engineer. Warmflow's own fault-finding guidance is explicitly directed at qualified engineers only.
How much does it cost to fix a Warmflow E16 fan fault in the UK?
For the most common repair — fan replacement including parts and labour — most homeowners pay in the region of £200–£380. If only the wiring needs attention, the bill can be towards the lower end of that range. In the rare worst-case scenario where the PCB also needs replacing, costs can rise to £450 or more; at that level, particularly on an older boiler, it is worth asking your engineer whether a new boiler represents better value long-term.
Will Warmflow's warranty cover the E16 fan fault?
Warmflow offers a 24-month warranty against defective parts and workmanship from the date of manufacture. If your boiler is within that window and the fault is down to a manufacturing defect, you may be covered. However, the warranty requires that the boiler has been serviced annually by a qualified engineer — if services have been missed, the warranty could be void. Check your paperwork and contact Warmflow directly to confirm your position before authorising any paid repairs.
My Warmflow boiler keeps showing E16 after reset — is something seriously wrong?
If E16 returns quickly after resetting, it strongly suggests a genuine component failure rather than a one-off glitch. Repeatedly resetting the boiler will not cure the underlying problem and may mask it from the engineer's diagnostics. Stop resetting and arrange for a Gas Safe engineer to carry out a proper inspection — the most likely culprits are a worn fan motor, seized bearings, or a damaged wiring connection.