Biasi E14 Fault Code: Causes, Fixes & Repair Costs
What does the Biasi E14 fault code mean?
The Biasi E14 (sometimes shown as ER 14 on the display) is a blocking lockout fault that fires when the boiler detects a problem with coolant circulation. In plain terms, the boiler's internal checks have found that water is either not moving through the system correctly or is overheating — most commonly because the circulation pump has slowed, seized, or lost communication with the control board. A secondary trigger is a faulty flow NTC (temperature sensor), which can send the boiler incorrect temperature readings and mimic a circulation failure. Because continued operation risks heat exchanger damage, the boiler shuts itself down and holds the lockout until the underlying fault is resolved.
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
- Circulation pump failure or seizure Common
The pump is the most frequent culprit. Over time, bearings wear, impellers seize — especially after a long summer lay-off — or the motor windings fail. Without adequate water movement, flow temperatures climb rapidly and the boiler locks out on E14.
- Pump set to the wrong speed Common
Most heating pumps have two or three speed settings. If the pump was installed or adjusted to a speed too low for the property's system, flow rates fall below the boiler's threshold. This is particularly common after a recent pump replacement where the speed wasn't matched to the system.
- Airlock trapped in the pump Common
Air introduced during a refill or system top-up can lodge in the pump volute, effectively blocking the impeller. The pump motor may still run but little or no water circulates, causing the boiler to register a circulation fault.
- Sludge or limescale restricting flow Sometimes
Magnetite sludge (broken-down corrosion from radiators and pipework) and limescale (common in hard-water areas) can clog the pump, plate heat exchanger, or narrow pipework. Either reduces flow enough to trigger E14 and can ultimately cause the flow temperature to exceed 105 °C.
- Blocked plate heat exchanger Sometimes
Heavy limescale or sludge accumulation inside the plate heat exchanger restricts water flow so severely that temperatures spike. The boiler interprets this overheating as a circulation failure and locks out.
- Faulty flow NTC temperature sensor Sometimes
If the NTC sensor that monitors flow temperature has drifted out of calibration, developed a wiring fault, or failed outright, it can report falsely high temperatures — convincing the boiler it has a circulation problem even when the pump is working normally.
- Damaged wiring or PCB fault Rare
Water ingress or vibration damage can break the signal path between the PCB and the pump. If the PCB cannot confirm the pump is running at the expected rate, it logs E14. A faulty PCB itself is the rarest cause but should be considered after everything else has been ruled out.
How to fix it
- Reset the boiler once (no more than twice) DIY safe
Press and hold the reset button for the time specified in your user manual — typically around 3 seconds. If the boiler fires and runs normally, monitor it closely. If E14 returns promptly, do not keep resetting; repeated lockouts without resolving the cause can cause further damage.
- Check your gas supply is live DIY safe
Confirm other gas appliances in the property (hob, fire) are working. If there is no gas supply, contact your gas supplier — this will not be related to E14 but rules out an unrelated outage.
- Check system pressure is correct DIY safe
Look at the pressure gauge on the boiler front panel. It should read between 1.0 and 1.5 bar when the system is cold. If it is below 0.8 bar, top it up via the filling loop following your boiler's user manual instructions. Low pressure alone rarely causes E14, but correcting it before calling an engineer saves time.
- Inspect and, if necessary, thaw a frozen condensate pipe DIY safe
In freezing weather, a blocked condensate pipe can cause various fault codes. Locate the plastic condensate pipe (usually exits through an outside wall) and check for ice. You can carefully pour warm — not boiling — water over the pipe to thaw it, then reset the boiler. If E14 persists after a successful thaw, the fault lies elsewhere.
- Do not attempt to access or adjust the pump yourself Gas Safe engineer
The pump is inside the boiler casing and is connected to sealed water circuits. Adjusting pump speed, bleeding the pump of air, or removing it requires draining parts of the system and is only safe when carried out by a Gas Safe registered engineer.
- Have an engineer inspect the pump — speed, airlock, and condition Gas Safe engineer
A Gas Safe engineer will check the pump's speed setting and adjust it to match your system's requirements. They will also locate the bleed screw on the pump body and release any trapped air. If the pump is seized or underperforming on a multimeter test, they will advise replacement.
- Have the system flushed if sludge or limescale is suspected Gas Safe engineer
The engineer will manually clean the pump and, where contamination is evident, perform a power flush or chemical flush of the heating circuit. Installing a magnetic filter (e.g. Magnaclean) at this stage helps prevent recurrence.
- Have the flow NTC sensor tested and replaced if faulty Gas Safe engineer
The engineer will check the sensor's resistance reading against expected values for the current water temperature. If the sensor is out of range, they will replace it — a relatively straightforward and low-cost repair.
- Have wiring, connections, and the PCB inspected Gas Safe engineer
If all other components test correctly, the engineer will trace the wiring from the pump to the PCB, looking for damaged insulation, corroded connectors, or loose terminals. PCB replacement is only recommended after all other causes are eliminated.
- Call a Gas Safe registered engineer if the fault persists Gas Safe engineer
If the boiler continues to lock out on E14 after any homeowner checks, contact a Gas Safe registered engineer. You can verify an engineer's registration at gassaferegister.co.uk. Biasi boilers are also supported by specialist heating engineers — ask specifically for experience with Biasi appliances.
Parts you may need
- Circulation pump (e.g. Grundfos UPS or equivalent Biasi OEM) · from £85
- Flow NTC temperature sensor · from £18
- Pump capacitor · from £12
- Plate heat exchanger (Biasi compatible) · from £95
- Magnetic system filter (e.g. Magnaclean Pro) · from £55
- PCB (Biasi main control board) · from £145
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 £120–£380, depending on the underlying cause.
Frequently asked questions
Can I fix Biasi E14 myself by resetting the boiler?
A single reset is worth trying — occasionally a transient airlock or sensor glitch will clear itself and the boiler will run normally afterwards. However, E14 is a lockout code triggered by a real mechanical or electrical fault in most cases. If the code returns after one or two resets, continuing to reset without investigation risks damaging the heat exchanger or pump. At that point you need a Gas Safe registered engineer.
How much does it cost to fix a Biasi ER 14 fault in the UK?
Most people pay somewhere between £120 and £380 depending on what is found. A straightforward fix — adjusting the pump speed or bleeding an airlock — might cost £120–£150 including the call-out. A full pump replacement with a quality unit such as a Grundfos typically comes to around £220–£280 all-in for parts and labour. A system power flush adds roughly £150–£250 on top. In the rare situation where the PCB needs replacing, costs can rise beyond £400, but engineers will only recommend this once cheaper components have been ruled out.
What is the difference between Biasi E14 and a pump airlock — and how does an engineer fix it?
An airlock is one specific cause of E14 rather than a separate fault. When air gets trapped inside the pump body it prevents the impeller from moving water effectively, and the boiler reads this as a circulation failure. An engineer fixes it by locating the small bleed screw on the front of the pump, briefly loosening it to allow the trapped air to escape, then re-tightening it before resetting the boiler. The whole job takes minutes once identified, making it one of the quickest and cheapest E14 resolutions.
Will sludge in my heating system cause Biasi ER 14 to keep coming back?
Yes — if magnetite sludge is the root cause and the system is simply reset or the pump replaced without flushing, the new pump will quickly accumulate the same debris and E14 will return. Ask your engineer to carry out a chemical or power flush at the same time as any component replacement, and have a magnetic filter fitted on the return pipe. This captures ongoing sludge and can be cleaned annually during a boiler service, significantly extending pump and heat exchanger life.