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Boiler with display and pressure gauge
Boiler fault codes

Intergas boiler faults: fault codes, causes and parts

All 70 fault codes for Intergas boilers, plus the faults that show no code. Type your code or choose your symptom.

In brief

A fault on an Intergas boiler usually means that the appliance has locked out or is reporting a fault code. Note the code on the display and look it up below: for each code you will find its meaning, checks you can safely do yourself and the parts that are often checked or replaced. Frequently searched: 5 (gas inlet pressure too low or drops…), 6 (flame detection fault), 29,30 (flame detection fault). No code? Check the water pressure (1.5 to 2 bar when cold), the power supply and the gas tap, and reset once. If the fault comes back, call in a certified gas engineer. If you smell gas, call your national gas emergency number or 112 immediately.

Most searched Intergas faults

These are the codes that visitors to this site search for most often.

See the 25 most searched fault codes of 2026, with the figures behind them →

Intergas boiler faults without a code on the display

Not every fault shows a code. These are the symptoms we come across most often with Intergas appliances, with what you can check yourself before calling someone out.

No hot water, but the heating works

The boiler heats the radiators but not the tap water. Check that the hot water function is switched on in the display (on some appliances it is called DHW mode or summer mode) and that the hot water valve under the boiler is open. If the water stays cold, this usually points to a fouled or leaking DHW heat exchanger, a faulty diverter valve or a DHW sensor giving incorrect readings. View the matching parts → Read the full explanation: no hot water, six causes →

Water pressure keeps dropping

Top up to 1.5–2 bar when cold and bleed the radiators. If the pressure drops again within a few days, the expansion vessel has often lost its pre-charge or there is a small leak in the system. A pressure relief valve that keeps dripping gives the same symptom. View the matching parts → Read the full explanation: water pressure keeps dropping – expansion vessel or leak? →

Boiler shuts down and locks out

The appliance shuts down and only starts again after a reset. Reset once; if the fault comes straight back, leave the reset button alone. Repeatedly resetting a locked-out boiler is not without risk: the safety device trips for a reason. View the matching parts → Read also: is the boiler cutting out because of a sensor or overheating? →

Radiators stay cold

Check that the thermostat is calling for heat, that the radiator valves are open and that the system has enough pressure. If everything stays cold while the boiler is firing, the circulation pump is often not running or the diverter valve is stuck in the hot water position. View the matching parts → Read the full explanation: radiators stay cold →

Ticking, humming or boiling noise

A banging noise at start-up usually points to air or limescale in the heat exchanger. A humming pump may have a worn bearing. A rattling fan is often rubbing or dirty. View the matching parts → Read also: replacing the fan – what to rule out first →

Water under the boiler

Check where it is coming from: the condensate drain (siphon blocked or cracked), the pressure relief valve (pressure too high or faulty expansion vessel) or a fitting. If in doubt, switch the boiler off and close the water supply. View the matching parts → Read the full explanation: water under the boiler – condensate or a leak? →

All 70 Intergas boiler fault codes

CodeCause
0Sensor fault after self-check
0 / 1Flow sensor error S1
0 / 2Return sensor error S2
0 / 3Hot water sensor error S3
0 / 4Cylinder sensor error S4
1Temperature too high
10Sensor fault S1
10, 11, 12, 13, 14Sensor fault S1
11Sensor fault S1
12Sensor fault S1
13Sensor fault S1
14Sensor fault S1
2S1 and S2 swapped
2Sensors S1 and S2 interchanged
20Sensor fault S2
20, 21, 22, 23, 24Sensor fault S2
21Sensor fault S2
22Sensor fault S2
23Sensor fault S2
24Sensor fault S2
27Short circuit of outdoor sensor
29Flame detection fault
29,30Flame detection fault
3Temperature lockout (S1) too large
30Flame detection fault
30Sensor error S3
4No flame signal
4No flame signal after 4 ignition attempts
40Cylinder sensor error S4
5Gas inlet pressure too low or drops out. Lower than 20 mbar.
5Condensate drain blocked
5Poor flame signal
5Poor flame signal detected
5Gas inlet pressure too low or drops out, lower than 20 mbar.
5No flame signal after 4 restart attempts
6Flame detection fault
7Parameters programmed with computer connection
8Fan speed incorrect
8Fan speed incorrect or fan does not start
AFan speed not at high setting within 1 minute
BBurner control unit faulty
CIncorrect gas valve connection or burner control unit faulty
DBurner control unit faulty
EBurner control unit faulty
FService button
FInternal fault
F of hInternal fault
F000Sensor S0 faulty
F001Temperature too high during central heating operation.
F002Temperature too high during DHW operation.
F003Flue gas temperature too high.
F004No flame during start
F005Flame loss during operation.
F006Flame simulation.
F007No or insufficient ionisation current.
F008Fan speed incorrect.
F009Internal burner control unit fault.
F010Sensor error S0.
F011Sensor error S0.
F012Sensor error S5.
F014Installation error sensor S0. Unwanted flow in the central heating circuit.
F016Installation error sensor S3.
F018Flue gas outlet and/or air supply blocked.
F019BMM error
F027Short circuit outdoor sensor S6.
F028Reset error.
F029Gas valve error.
F031Sensor error S1/unknown error.
Geen codeAppliance is switched off
HInternal fault

Order parts for your Intergas boiler

Intergas parts are available from Instalpunt; shipping to EU countries from €12.95 (€16.95 for more distant countries), usually 3–5 working days.

Parts per Intergas-series: Kombi Kompakt HRE · Kombi Kompakt HReco · Kombi Kompakt HR · Xtreme · Xtend · Prestige.

View Intergas parts →

Frequently asked questions about Intergas faults

What does a fault on an Intergas boiler mean?

The appliance is reporting that it has shut itself down or cannot continue. The code on the display points to the group of causes: ignition, water pressure, a sensor, the fan or communication with the thermostat. The table above shows, for each code, what Intergas means by it.

How do I reset my Intergas boiler?

The reset button is on the control panel of your Intergas boiler; on most appliances you hold it down for two to five seconds until the display responds. Reset once. If the same fault comes straight back, resetting will not solve it and a part or a setting needs attention. Always consult the manual for your model: the position of the button and how long to press it differ per series.

Can I fix an Intergas fault myself?

You can top up the water pressure, bleed the system, replace filters and clean a siphon yourself. Anything behind the sealed section of a gas appliance is a different matter: work on the gas valve, burner, heat exchanger and flue must be carried out by a certified gas engineer.

How much does it cost to fix a fault?

That depends on the cause and whether a part is needed. With us you can see the part straight away with its price and delivery time, so you know where you stand in advance. If you call in an engineer, always ask about the call-out charge and hourly rate before they come.

Where can I find the right part for my Intergas?

Check the rating plate for the exact type and use it to search our catalogue, or search directly by the manufacturer number of the faulty part. Each part lists the appliances it fits.

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