Intergas F008 Fault Code: Causes, Fixes & Repair Costs
What does the Intergas F008 fault code mean?
The F008 code appears on Intergas boilers (including the Xclusive and Xtreme ranges) when the PCB detects that the fan is running at the wrong speed — either too slowly or erratically. Because the fan is responsible for safely pushing combustion gases out through the flue, the boiler will lock out immediately as a precaution. Without a correctly running fan, harmful waste gases could build up inside the appliance, so the boiler will refuse to ignite until the fault is resolved and the unit is reset by a qualified 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
- Faulty or failing fan Common
The fan does not need to stop completely to trigger F008 — a speed that is simply below the threshold the PCB expects is enough to lock the boiler out. Fans can wear over time, develop bearing problems, or accumulate debris that slows their rotation. This is the most common root cause of this fault code.
- Faulty air pressure switch Sometimes
The air pressure switch monitors airflow inside the boiler and reports back to the PCB, which uses those readings to confirm the fan is running correctly before allowing ignition. A switch that has stuck, developed a leak in its sensing tube, or failed electronically can send false readings — making the PCB believe fan speed is wrong even when the fan itself is perfectly healthy.
- Wiring fault between fan and PCB Sometimes
Intergas engineer documentation specifically flags fan wiring as a diagnostic check for F008. A loose connector, a damaged wire, or corrosion on a terminal can interrupt the speed-feedback signal from the fan to the PCB, causing the board to register an incorrect or missing speed reading.
- PCB failure Rare
If the PCB itself is faulty, it may misinterpret or fail to receive the fan-speed signal correctly, triggering F008 even though the fan, wiring, and air pressure switch are all in good working order. PCB faults are the least common cause but should be considered once other components have been ruled out.
How to fix it
- Check that your gas supply is working DIY safe
Before assuming the boiler has a component fault, confirm that other gas appliances in your home — such as a hob or gas fire — are working normally. If there is no gas supply to the property, contact your gas supplier rather than a boiler engineer.
- Attempt a single reset DIY safe
Press and hold the reset button on your Intergas boiler as described in your user manual. If the boiler fires up and runs normally, monitor it closely over the next hour or two. If F008 returns promptly, do not keep resetting — repeated resets will not fix an underlying fault and may mask the problem from an engineer's diagnostics.
- Call a Gas Safe registered engineer to inspect the fan Gas Safe engineer
An engineer will run the boiler in diagnostic mode and measure whether the fan is reaching its required speed. If the fan is running too slowly or drawing incorrect current, it will need to be replaced. Intergas spare fans sometimes require next-day ordering, so allow two to three days for the repair to be completed.
- Engineer to test the air pressure switch and its sensing tube Gas Safe engineer
The engineer will check the air pressure switch for correct operation and inspect the rubber sensing tube that connects it to the fan housing. A cracked or blocked tube, or a switch that has failed internally, will cause F008 even with a perfectly functional fan and can be replaced at a fraction of the cost of a new fan.
- Engineer to inspect fan wiring and connectors Gas Safe engineer
Following Intergas's own diagnostic guidance, the engineer should check all wiring between the fan and PCB — looking for loose pins, corroded terminals, or chafed insulation. A wiring repair is typically quick and inexpensive if caught at this stage.
- Engineer to test the PCB if all other components check out Gas Safe engineer
If the fan, air pressure switch, and wiring are all confirmed to be in good order, the PCB becomes the prime suspect. The engineer can test voltages and inspect solder joints to determine whether the board needs replacing or repairing. This is the most expensive outcome, so a thorough engineer will exhaust the other possibilities first.
Parts you may need
- Intergas boiler fan (model-specific) · from £90
- Air pressure switch · from £35
- Fan sensing tube / pressure switch hose · from £8
- PCB (Intergas Xclusive / Xtreme) · from £180
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–£400, depending on the underlying cause.
Frequently asked questions
Can I just keep resetting the boiler to clear F008?
Resetting the boiler is worth trying once to see whether the fault clears itself, but repeated resets are unlikely to help and are not recommended. F008 is a safety lockout triggered because the PCB has detected an unsafe fan speed. If the underlying cause — whether that is a worn fan, a faulty air pressure switch, or a wiring issue — is not addressed, the boiler will simply lock out again. An engineer needs to diagnose and fix the root cause before the boiler will run reliably.
How much does it cost to fix an Intergas F008 fault?
The total cost depends on which component is at fault. A fan replacement typically comes to around £250 all-in (parts and labour), while an air pressure switch replacement is usually around £200. A PCB replacement tends to fall in the £180–£400 range depending on the specific Intergas model. Most engineers also charge a diagnostic or call-out fee of £60–£100 to identify the fault before carrying out the repair, so factor that into any quotes you receive. Make sure quotes include VAT and a follow-up test after the repair.
Is F008 dangerous — should I leave my house?
You do not need to evacuate, but you should not attempt to run the boiler or bypass the lockout. The boiler has shut down precisely to prevent a situation where combustion gases are not safely vented. Leave the boiler off and arrange for a Gas Safe engineer to visit as soon as reasonably possible. If you smell gas at any point, that is a separate and urgent emergency — leave the property, do not operate any switches, and call the National Gas Emergency Service on 0800 111 999.
Which Intergas models are affected by F008?
F008 is documented in the official Intergas engineer manuals for the Xclusive and Xtreme ranges, but it can appear on other Intergas models that use the same control system, including the HRe and Compact HRe. The fan-speed monitoring logic is common across the range, so the causes and diagnostic approach are broadly the same regardless of which Intergas boiler you own.