Biasi E69 Fault Code: Causes, Fixes & Repair Costs
What does the Biasi E69 fault code mean?
The E69 (sometimes displayed as ER 69) fault code on Biasi boilers signals one of two closely related problems: either the boiler's PCB (printed circuit board) has not been correctly configured — for example after a new installation or a board replacement — or the control board has detected an electrical or wiring fault serious enough to trigger a safety lockout. In both cases the boiler shuts down and will not fire until the underlying issue is resolved. Because the PCB is the central controller that manages the gas valve, ignition, and all safety systems, any configuration gap or wiring irregularity here is treated as a critical fault. This is not a fault a homeowner can resolve themselves; it requires a Gas Safe registered engineer to diagnose and repair safely.
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
- PCB not configured after installation or board replacement Common
When a Biasi boiler is first installed, or when the PCB is replaced, the new board must be programmed with the correct product configuration code for that specific model. If this step is skipped or interrupted, the boiler displays E69 and refuses to run. This is the single most common trigger for this code — particularly on relatively new installations or boilers that have recently had board work carried out.
- Loose or disconnected wiring harness Common
The PCB communicates with every major component via a network of wiring connectors. Vibration, thermal expansion and contraction over years of use can work connectors loose, causing the board to lose contact with a critical circuit. The boiler's safety logic interprets this as an electrical fault and locks out. Loose connectors are often intermittent, so the fault may clear on reset only to return shortly afterwards.
- Moisture or water damage to the PCB Sometimes
An internal water leak — from a corroded heat exchanger, a failing pump seal, or a loose pipe joint — can allow water droplets to reach the PCB. Even a small amount of moisture can cause short circuits, track corrosion, or component burnout on the board, leading to a configuration or electrical fault code. The source of the leak must be fixed before any board work is carried out.
- Deteriorated solder joints on the PCB Sometimes
Years of repeated heating and cooling cycles cause the solder joints on the PCB to micro-crack. A cracked joint may maintain contact when the boiler is cold but open up once the board warms, producing apparently random or intermittent E69 faults. This type of failure is more common on older Biasi boards and can sometimes be confirmed by the fault clearing after the boiler cools overnight.
- PCB component failure or damage Rare
Beyond solder joints, individual components on the board — capacitors, relays, or driver chips — can fail with age or after a power surge. A damaged component may prevent the board from holding its configuration or completing its self-check, resulting in a persistent lockout. In this scenario the board itself will need to be replaced.
How to fix it
- Switch the boiler off at the programmer or room thermostat and attempt a single reset DIY safe
Press and hold the reset button on the boiler's front panel as described in your user guide (usually 3–5 seconds). Allow the boiler a full minute to complete its start-up sequence. If it fires and runs normally, monitor it closely over the next 24 hours. A one-off reset is safe; however, if E69 returns after one or two attempts, stop resetting — repeated resets on an underlying electrical or configuration fault can cause further damage to the PCB.
- Check that your gas supply is working DIY safe
Confirm other gas appliances in your home (hob, gas fire) are working normally. If no gas appliances are functioning, contact your gas supplier. If other appliances are working fine, the gas supply to the boiler is not the cause and the fault lies internally.
- Note when the fault first appeared and whether any recent work was done DIY safe
Before calling an engineer, make a note of: when E69 first appeared, whether the boiler was recently installed or serviced, whether the PCB was recently replaced, and whether the fault is intermittent or constant. This information helps the engineer narrow down the cause quickly and reduces diagnostic time — potentially saving you money.
- Do not open the boiler casing or touch internal wiring Gas Safe engineer
The E69 code is rooted in electrical and PCB-level faults. Opening the boiler casing and handling internal wiring or the PCB without Gas Safe registration is both illegal and dangerous. It can void any remaining manufacturer warranty (Biasi offer 5–7 years on most models) and risks electric shock or unsafe boiler operation. Leave all internal investigation to a qualified engineer.
- Arrange for a Gas Safe registered engineer to diagnose and repair the fault Gas Safe engineer
A qualified engineer will: (1) check the PCB configuration code and re-programme the board if it has not been set up correctly; (2) inspect all wiring harnesses and connectors for looseness, corrosion, or damage; (3) check the boiler internally for signs of water leaks that may have caused moisture damage to the board; (4) test the PCB itself and, if faulty, advise on repair or replacement. Always ask for the engineer's Gas Safe registration number before they start work — you can verify it at gassaferegister.co.uk.
Parts you may need
- Biasi PCB (control board) · from £220
- Wiring loom / harness · from £55
- PCB connector repair kit · from £15
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 £100–£380, depending on the underlying cause.
Frequently asked questions
Can I fix the Biasi E69 fault myself by resetting the boiler?
A single reset is worth trying, but E69 is fundamentally an electrical or PCB configuration fault that a reset will not cure if there is an underlying problem. If the code returns after one or two resets, stop — continuing to reset can cause further damage to the control board. You need a Gas Safe registered engineer to investigate and carry out the repair.
Why has E69 appeared after my Biasi boiler had its PCB replaced?
This is actually one of the most common reasons for E69: the replacement PCB has not been configured with the correct product code for your specific Biasi model. The engineer who fitted the board needs to re-programme it using the configuration procedure in the Biasi service manual. Once the code is correctly entered, E69 should clear and the boiler should operate normally.
How much does it cost to fix a Biasi E69 fault?
Most E69 repairs fall somewhere between £100 and £380. A straightforward wiring reconnection or PCB re-configuration at the lower end, and a full wiring loom repair or minor component replacement at the higher end, typically land within that range. PCB replacement is a bigger job — parts alone can cost £180–£250, and with labour the total is often £350–£550. As a general rule, if a repair quote approaches or exceeds £500 it is worth comparing the cost against a new boiler, particularly if your Biasi is already outside its warranty period.
Is it safe to keep using the boiler with an E69 code showing?
No. E69 is a lockout code, meaning the boiler has shut itself down and will not fire while the fault is active. Even if the boiler appears to clear after a reset, the underlying electrical or configuration fault remains and could affect safe operation. Do not attempt to use a boiler that is displaying a persistent E69 — contact a Gas Safe registered engineer as soon as possible.