Intergas F016 Fault Code: Causes, Fixes & Repair Costs
What does the Intergas F016 fault code mean?
The F016 code appears on Intergas Xclusive and Xtreme boilers when the burner controller detects a problem with the S3 domestic hot water (DHW) temperature sensor — the sensor responsible for monitoring the temperature of the hot water your boiler produces. The boiler locks out as a precaution until the issue is resolved. The fault specifically flags a mounting or positional problem with the sensor first, though a wiring fault or failed sensor can produce the same code. A closely related code, F030, also relates to the S3 sensor but points more directly to a sensor component failure rather than a mounting issue — if you see F030 after investigating F016, the sensor itself has likely failed electrically.
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
- S3 sensor dislodged from pipe Common
The most common cause of F016. The S3 DHW NTC sensor clips onto the hot water pipe inside the boiler, and over time — or after previous servicing — it can work loose or be accidentally knocked out of position. When not properly seated against the pipe, the sensor cannot read the water temperature accurately and the boiler locks out.
- Wiring fault to S3 sensor Sometimes
The wiring harness connecting the S3 sensor to the burner controller can develop a loose connector, a broken wire, or corrosion at the terminal. Even a brief open circuit in the wiring will cause the controller to see an out-of-range signal and trigger F016.
- Failed S3 NTC sensor Sometimes
The S3 sensor is a negative temperature coefficient (NTC) thermistor whose resistance should drop predictably as temperature rises. If the sensor has degraded or failed, its resistance will fall outside the expected range even when correctly mounted and wired. An engineer will confirm this with a multimeter reading.
How to fix it
- Check your gas supply is on DIY safe
Before assuming the boiler is faulty, confirm that your gas supply is working — check that other gas appliances such as a hob or gas fire are functioning normally. If your gas supply has been interrupted, contact your gas supplier.
- Attempt a boiler reset (up to twice) DIY safe
On Intergas Xclusive and Xtreme models, the reset procedure involves pressing and holding the relevant combination of buttons until the fault symbol clears and C000 appears on the left side of the display. Consult your model's user manual for the exact button combination. Do not reset more than two or three times — repeated resets without fixing the underlying fault can mask the problem.
- Visually check that the S3 sensor is clipped onto the pipe Gas Safe engineer
A Gas Safe engineer will open the boiler casing and locate the S3 DHW sensor. If it has simply come loose from its mounting clip on the hot water pipe, re-seating it correctly is the quickest and cheapest resolution. This step requires access to the inside of the boiler and must be carried out by a registered engineer.
- Inspect the S3 sensor wiring and connectors Gas Safe engineer
The engineer will trace the wiring from the S3 sensor back to the burner controller, checking for damaged insulation, corroded terminals, or a loose plug. A multimeter is used to test continuity. Any damaged wiring will need to be repaired or replaced.
- Test S3 sensor resistance and replace if out of specification Gas Safe engineer
Using a multimeter, the engineer will measure the resistance of the S3 NTC thermistor at a known temperature and compare the reading against Intergas's specification. An out-of-range or open-circuit reading confirms sensor failure. The replacement part (Intergas part number 200177) is widely available from UK boiler parts suppliers and is a relatively inexpensive component.
- Reset the boiler and verify normal operation Gas Safe engineer
Once the engineer has corrected the mounting, wiring, or replaced the sensor, the boiler is reset and run through a hot water demand cycle to confirm the fault has cleared and the S3 sensor is reading temperatures correctly.
- Contact a Gas Safe registered engineer if you have not already done so DIY safe
If the fault persists after your own visual checks, or if you have not been able to resolve it, call a Gas Safe registered engineer. You can find one at the Gas Safe Register website (gassaferegister.co.uk). Intergas also offer their own repair service — contact them on 01527 888000 or at service@intergasheating.co.uk. If your boiler is within its warranty period and has been serviced annually by a Gas Safe engineer, this repair may be covered at no charge.
Parts you may need
- Intergas S3 DHW NTC Temperature Sensor (part no. 200177) · from £30
- Wiring harness / sensor loom (if damaged) · from £45
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 £90–£280, depending on the underlying cause.
Frequently asked questions
What is the difference between Intergas fault codes F016 and F030?
Both codes relate to the S3 domestic hot water temperature sensor, but they indicate different problems. F016 is a mounting fault — the boiler's controller has detected that the sensor is not correctly positioned on the pipe, or its signal suggests it is not making proper contact. F030 is a general S3 sensor fault, pointing more directly to an electrical failure of the sensor component itself. If an engineer re-seats the sensor and the fault returns as F030, the sensor has most likely failed and will need replacing.
Can I fix Intergas F016 myself?
There is a limited visual check you can safely carry out: confirm the boiler reset clears the fault, and check that your gas supply is working. However, diagnosing and correcting the S3 sensor position, testing wiring, or replacing the sensor all require you to open the boiler casing — work that must only be done by a Gas Safe registered engineer. Attempting it yourself is illegal for gas appliances and could invalidate your warranty.
How much does it cost to fix an Intergas F016 fault in the UK?
The cost depends on what is actually wrong. If the sensor has simply come loose and needs re-clipping, you are largely paying the engineer's call-out fee — typically £90–£150. If the sensor needs replacing, the part (Intergas part 200177) costs around £20–£40, so the total bill including labour is usually £120–£250. If wiring is damaged and takes longer to diagnose or repair, costs can reach £250–£280. In rare cases where a PCB fault is mimicking an S3 reading error, costs would be higher — but this is uncommon for F016.
Is my Intergas boiler still under warranty for an F016 fault?
Intergas offer generous warranty periods: ten years on the Xclusive range, seven years on the Xtreme and HRE ranges, and shorter periods on other models. Warranty cover is usually conditional on annual servicing by a Gas Safe registered engineer. If your boiler is within the warranty period and has been serviced correctly, contact Intergas directly on 01527 888000 or at service@intergasheating.co.uk — the repair may be covered at no cost to you.