Intergas Boiler Error Code 11
With code 11 there is a short circuit in the circuit of flow sensor S1. The boiler cannot measure the flow temperature reliably and stops. The sensor or the wiring must be tested and replaced by an installer.
Applies to: Intergas HRE and Kombi Kompakt
Common causes
- Short circuit in flow sensor S1 itself
- Damaged or trapped sensor wiring causing a short circuit
What to check, in order
- Note the code and reset the boiler once.
- Check the water pressure and bleed the system; a fault that returns immediately points to the sensor itself.
- Have an installer test sensor S1 and the wiring and replace them if needed.
Clear the code and test
- Fix what the checks above found first — pressure topped up, a radiator bled, the thermostat set right. Resetting without fixing the cause only brings the code back.
- Make sure the boiler has power and the gas tap at the boiler is open.
- If the water pressure is below 1.5 bar, top it up to between 1.5 and 2 bar with the filling loop, as your manual shows.
- Press the reset button once and watch a full cycle: the boiler should start, heat the radiators or the tap water, and keep running without the code coming back.
When to call a professional
This code usually points to a faulty part, wiring or the control board on a Intergas boiler. Run the checks above to rule out the simple causes, then book a technician — and book one straight away if any of these apply:
- The code comes back after you have run the checks and a test cycle.
- You smell burning, see sparks or scorch marks, or the breaker trips.
- Water is leaking and you cannot stop it.
- The fix needs panels opened beyond what your manual describes, or a part tested with a meter, and you are not set up for that.
When you call, give the brand, the code 11, your model number (on a label on the type plate, usually at the bottom or on the side of the boiler) and the checks you already ran. It shortens the visit.
Repair or replace?
This fault is in professional territory: the fix usually means a major part or board-level work, and the labour adds up. If your machine is already well into its service life, get the repair quote first, then compare it with the price of a current equivalent model before you decide. Paying a large share of a new machine's price to repair an old one is rarely the better deal; replacing a machine over one cheap fault is wasteful too.
Parts that may be involved
Flow sensor S1
Parts are model-specific. Find your model number first — usually on a label on the type plate, usually at the bottom or on the side of the boiler — and match the part to that number before ordering.
Questions people ask about 11
What does 11 mean on a Intergas boiler?
11 means: Short circuit in flow sensor S1. With code 11 there is a short circuit in the circuit of flow sensor S1. The boiler cannot measure the flow temperature reliably and stops. The sensor or the wiring must be tested and replaced by an installer.
Can I fix Intergas 11 myself?
Only the preliminary checks. Code 11 usually means a part, wiring or the control board has failed, which is a technician job. Run the checks to rule out simple causes before you book.
How do I clear Intergas 11?
Fix what the checks above found first — pressure topped up, a radiator bled, the thermostat set right. Resetting without fixing the cause only brings the code back. Make sure the boiler has power and the gas tap at the boiler is open. If the water pressure is below 1.5 bar, top it up to between 1.5 and 2 bar with the filling loop, as your manual shows.
Sources checked
- Intergas HRE Parameter List / Fault Finding (manufacturer document)
- Warmgarant: Intergas storingscodes
The meaning and checks for this code were checked against the sources above in November 2026. Codes vary by model and region; if your manual lists a different meaning for your exact model, follow the manual.