Intergas F030 Fault Code: Causes, Fixes & Repair Costs
What does the Intergas F030 fault code mean?
The F030 code appears on Intergas Xtreme and Xclusive boilers when the control board detects a problem with the S3 sensor — the NTC thermistor responsible for monitoring domestic hot water (DHW) temperature. The boiler relies on this sensor to measure and regulate the temperature of the water supplied to your taps and showers. When the sensor returns a reading that falls outside the expected range — or no reading at all — the boiler raises F030 and may lock out to prevent unsafe operation. The underlying issue is usually a dislodged sensor, a degraded thermistor, or a fault in the wiring between the sensor and the PCB.
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
- Dislodged or incorrectly seated S3 sensor Common
The S3 is a clip-on NTC thermistor that attaches directly to a 15mm pipe inside the boiler. Vibration, previous servicing, or general wear can cause the clip to work loose over time, pulling the sensor away from good thermal contact with the pipe. Even a small gap is enough to produce wildly inaccurate readings and trigger F030.
- Failed or degraded DHW sensor Common
NTC thermistors degrade gradually, and the S3 is no exception. As the sensor ages its resistance characteristics drift, causing the boiler's control board to receive temperature readings that no longer match reality. A failed sensor may also produce an open-circuit or short-circuit reading. The genuine Intergas replacement part is 200177 — a like-for-like clip-on thermistor that is widely available from UK boiler parts suppliers at a relatively low cost.
- Damaged, corroded, or disconnected wiring Sometimes
The lead and connector running from the S3 sensor to the PCB can suffer corrosion — especially in boilers that have experienced any internal water ingress — or physical damage. A corroded connector can introduce enough resistance to mimic a failed sensor, while a broken wire will produce an open-circuit fault. The engineer will check continuity and inspect the connector before condemning the sensor itself.
- Water ingress or internal leak damage Rare
Internal leaks from pump seals, heat exchanger joints, or loose pipe connections can allow water to track along wiring looms and reach sensor connectors or even the PCB. If F030 appears on a relatively young boiler, or if the sensor and wiring both check out correctly, the engineer should look for evidence of a current or previous internal leak as the root cause of the electrical fault.
How to fix it
- Check that your gas supply is working DIY safe
Before anything else, confirm that other gas appliances in your home (hob, gas fire) are working normally. If there is no gas supply to the property, contact your gas supplier rather than investigating the boiler further.
- Reset the boiler once DIY safe
Press and hold the reset button for approximately five seconds, then release it. Allow the boiler a couple of minutes to attempt a restart. If F030 returns immediately, do not keep resetting — repeated resets will not cure a sensor fault and may mask the problem for an engineer. Limit resets to no more than two or three attempts in total.
- Engineer to locate and inspect the S3 sensor mounting Gas Safe engineer
A Gas Safe registered engineer will access the boiler internals and locate the S3 DHW sensor on its 15mm pipe. If the clip has become dislodged or the sensor has shifted out of position, correctly re-seating it may be all that is needed. This is quick to check and should always be the first physical step.
- Engineer to inspect wiring and connector integrity Gas Safe engineer
The engineer will trace the S3 wiring loom back to its connector on the PCB, checking for signs of corrosion, chafing, or water damage. A corroded connector can often be cleaned or replaced at low cost; a damaged loom section may need splicing or a replacement harness.
- Engineer to measure sensor resistance Gas Safe engineer
Using a multimeter, the engineer will measure the S3 thermistor's resistance at both ambient and operating temperatures and compare the readings against the expected NTC resistance curve for that sensor. Guessing with thermistors leads to misdiagnosis — a proper resistance test confirms whether the sensor itself is at fault before parts are ordered.
- Engineer to replace the S3 sensor if faulty Gas Safe engineer
If resistance readings confirm the sensor has failed or drifted out of specification, the engineer will fit a replacement. The genuine Intergas S3 DHW sensor (part number 200177) is a direct clip-on replacement and is readily available from UK boiler parts suppliers, typically on next-day delivery if not already on the van.
- Engineer to investigate for internal water damage if sensor and wiring are sound Gas Safe engineer
If the sensor and wiring both pass testing but F030 persists, the engineer should look for evidence of an internal water leak — inspect the pump seal, heat exchanger joints, and pipe connections. Water tracking along wiring looms can corrupt PCB inputs and cause sensor fault codes even when the sensor itself is fine. Addressing a leak early avoids far more expensive repairs later.
- Call a Gas Safe registered engineer if you have not already done so Gas Safe engineer
F030 cannot be resolved by homeowner action beyond the initial reset. If the fault persists after one or two resets, contact a Gas Safe registered engineer to carry out the diagnostic and repair steps above. You can verify an engineer's registration at gassaferegister.co.uk. If your boiler is out of warranty, Intergas also offer a fixed-price out-of-warranty repair service where parts and labour are covered for one year.
Parts you may need
- Intergas S3 DHW NTC Temperature Sensor (part no. 200177) · from £25
- Sensor wiring harness / connector · from £20
- Intergas PCB (control board) · from £320
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–£220, depending on the underlying cause.
Frequently asked questions
Can I fix Intergas F030 myself by resetting the boiler?
A single reset is worth trying — press and hold the reset button for around five seconds and give the boiler a couple of minutes to restart. However, F030 is a sensor fault, not a temporary glitch, so if the code returns after one or two resets the underlying cause will need proper diagnosis by a Gas Safe registered engineer. Repeatedly resetting without addressing the fault will not cure it.
How much does it typically cost to fix an Intergas F030 fault?
For the most common scenario — a dislodged or failed S3 sensor — you should expect to pay roughly £120 to £220 all-in, covering the engineer's call-out, labour, and the replacement sensor (part 200177 costs around £15–£40). If wiring damage is found, the repair may sit at the higher end of that range. In the uncommon situation where the PCB has been damaged by water ingress, a PCB replacement adds significantly more to the bill — typically around £450 including parts and labour — though this is unusual for a straightforward F030 fault.
What is the difference between Intergas fault codes F030 and F031?
Both codes relate to NTC temperature sensors, but they monitor different circuits. F030 indicates a fault with the S3 sensor, which tracks domestic hot water temperature. F031 relates to the S1 sensor, which monitors the central heating flow temperature. The diagnostic approach is similar for both, but they are physically different sensors in different locations inside the boiler.
My Intergas boiler is over ten years old — is it worth repairing an F030 fault?
If the repair is a straightforward sensor replacement costing £120–£220 and the rest of the boiler is in good condition, repair is almost always worthwhile on a ten-year-old boiler. However, if the engineer finds that water ingress has caused wider damage — for example to the PCB — the combined repair cost may start to approach the price of a new boiler. Intergas boilers have a good reputation for reliability, so discuss the full picture with your engineer before committing to expensive secondary repairs on an older appliance.