Ravenheat E05 Fault Code: Causes, Fixes & Repair Costs
What does the Ravenheat E05 fault code mean?
The E05 fault code on Ravenheat boilers signals a problem with the boiler's flue fan. The fan is responsible for expelling combustion gases safely out through the flue, and the boiler's control board continuously monitors it to confirm it is running correctly before and during a heating or hot water demand. If the PCB cannot verify that the fan is operating as expected — whether because the fan itself has failed, the wiring is damaged, or the board is misreading the signals — it will lock the boiler out entirely as a safety precaution. This means you will have no heating and no hot water until the underlying fault is diagnosed and resolved. The E05 code appears across Ravenheat's CS, CSI, WH, and HE series boilers.
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
- Burnt-out or seized fan motor Common
Over time the motor windings can burn out or the bearings inside the fan assembly can seize, preventing the fan from spinning at the speed the PCB expects. This is the most frequent reason for an E05 and typically means the fan unit needs replacing outright.
- Damaged or loose fan wiring Common
The wiring loom connecting the fan to the PCB can develop loose connections at the plug, chafe against the boiler casing, or suffer heat-related deterioration. A break or high-resistance connection in this circuit will prevent the board from receiving a proper fan-speed signal even if the motor itself is fine.
- Faulty air pressure switch Sometimes
The air pressure switch confirms that the fan is generating adequate airflow through the heat exchanger before ignition is permitted. If the diaphragm inside the switch cracks or the rubber tubing connecting it to the fan becomes blocked or split, the switch may fail to close and the boiler interprets this as a fan fault.
- PCB fault or faulty fan relay on the PCB Sometimes
The PCB contains a relay that switches power to the fan and a circuit that reads the fan's tachometer signal. If either of these fails, the board may not send power to the fan at all, or it may receive no feedback signal and assume the fan is not running — triggering E05 even when the fan hardware is perfectly serviceable.
- Blocked or restricted flue Rare
A partial blockage in the flue or air intake — caused by bird nests, debris, or a damaged terminal — can put excessive back-pressure on the fan, causing it to run slowly or stall. The PCB detects the abnormal speed and raises E05.
How to fix it
- Reset the boiler once or twice DIY safe
Locate the reset button or switch on your Ravenheat boiler (refer to your user manual if unsure of its position) and hold it for the time specified — usually around three seconds. Wait for the boiler to attempt a restart. If the E05 code clears and the boiler runs normally, monitor it over the next 24 hours. If the code returns promptly or does not clear at all, move on to the next steps. Do not repeatedly reset more than two or three times, as this will not fix an underlying mechanical fault and could mask a safety issue.
- Check your gas supply DIY safe
Confirm that other gas appliances in your home — your hob or gas fire, for example — are working normally. If they are not, there may be a wider gas supply interruption; contact your gas network operator. If other appliances work fine, the gas supply to the boiler is not the issue here.
- Visually inspect the external flue terminal DIY safe
From outside your property, look at the flue terminal on the wall or roof. Check whether it appears physically blocked by debris, a bird nest, ice, or obvious damage. Do not attempt to dismantle or reach inside the flue. If you can see a clear obstruction at the terminal that is safely accessible at ground level, removing it may help, but in most cases a Gas Safe engineer should inspect the full flue run.
- Do not attempt to access, test, or replace the fan or any internal components Gas Safe engineer
Removing the boiler casing and working on the fan, its wiring, the air pressure switch, or the PCB requires Gas Safe registration. Undertaking this work without the correct qualifications is illegal under UK gas safety regulations and potentially dangerous. Leave all internal diagnosis and repair to a qualified engineer.
- Contact a Gas Safe registered engineer to diagnose and repair the fault Gas Safe engineer
A qualified engineer will remove the casing safely and carry out a structured diagnosis: testing the fan motor for burnout or seized bearings; checking the wiring loom and connectors for continuity and damage; testing the air pressure switch and its connecting tubing; and using a multimeter to confirm the PCB is correctly powering the fan and reading its speed signal. Once the faulty component is identified, they will advise on repair or replacement. Given that a fan replacement on an ageing boiler can cost £200–£350 including labour, it is worth asking the engineer for an honest assessment of whether the boiler's overall condition justifies the repair cost or whether a new boiler would be a more economical long-term choice.
Parts you may need
- Ravenheat replacement flue fan assembly · from £145
- Air pressure switch · from £35
- Fan wiring loom / harness · from £25
- PCB (printed circuit board) · from £220
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
Is the Ravenheat E05 fault dangerous?
The boiler locks itself out when E05 appears specifically to prevent unsafe operation — combustion gases could build up in the property if the fan were to stop while the burner was alight. So while a locked-out boiler is inconvenient, the lockout itself is the safety system working correctly. Do not attempt to bypass the lockout or repeatedly reset the boiler in an effort to keep it running. Get a Gas Safe engineer to resolve the root cause.
Can I fix the E05 fault myself?
There is very little a homeowner can safely do beyond attempting a reset (once or twice) and checking the external flue terminal for obvious blockages. All internal work — testing the fan, inspecting wiring, checking the air pressure switch, or touching the PCB — must be carried out by a Gas Safe registered engineer. Working on a gas boiler without Gas Safe registration is illegal in the UK and potentially life-threatening.
How much will it cost to fix a Ravenheat E05 fault?
For the most common repair — replacing the fan — you should budget roughly £200–£380 including parts and labour. The fan unit itself typically costs £100–£200 depending on your exact Ravenheat model, and a Gas Safe engineer will usually charge £50–£80 per hour for labour. If the PCB is at fault rather than the fan, the PCB alone can cost £200–£300 or more for the part, making the total repair considerably higher. In that scenario — particularly if your boiler is over 10 years old — it is often more cost-effective to invest in a new boiler rather than repair the existing one.
My Ravenheat boiler shows E05 but the fan appears to be spinning — why?
This is not unusual. The boiler's PCB does not just check whether the fan is moving; it monitors the fan's speed via a tachometer signal. If the fan is spinning more slowly than expected — due to worn bearings, a partial winding fault, or a restricted flue — the board can still trigger E05. Equally, a faulty PCB relay or damaged wiring can prevent the board from reading the speed signal correctly, causing an E05 even when the fan is running at full speed. A Gas Safe engineer will use a multimeter to test both the fan output and the PCB's response to determine which component is actually at fault.