FAQ
TL;DR: In this thread, 1/1 cases of EOLO Star 24 3 E “Error 11” were fixed by replacing the exhaust pressure switch; “Replacement of the exhaust pressure switch helped.” [Elektroda, omaxp, post #17267860]
Why it matters: It prevents unsafe workarounds like opening the top lid and restores safe, reliable heating for owners facing Error 11.
Quick Facts
- Error 11 on EOLO Star 24 3 E refers to the exhaust/airflow pressure switch fault reported by the owner. [Elektroda, omaxp, post #16790736]
- This boiler has a closed turbo chamber; it draws combustion air from outside, not the room. [Elektroda, irus.m, post #16793106]
- Reported fix: replace the exhaust pressure switch; issue cleared post-replacement. [Elektroda, omaxp, post #17267860]
- Reported cost benchmark: PLN 200 for the part + PLN 100 labor (historical). [Elektroda, omaxp, post #19979162]
- Do not run with the top white cap open; “This cap should be screwed on.” CO risk noted. [Elektroda, Piotr2608, post #16791369]
What does Error 11 mean on an EOLO Star 24 3 E gas boiler?
Error 11 indicates a fault on the exhaust/airflow pressure switch circuit. The owner observed the fault repeating. It cleared only when the top white lid was opened, which is unsafe. The code flags inadequate airflow or a switch-related issue that prevents safe ignition. Keep the lid closed and investigate the flue/air path and the switch. [Elektroda, omaxp, post #16790736]
Is it safe to run the boiler with the white top lid open?
No. “This cap should be screwed on.” Running with the lid open risks unsafe combustion and carbon monoxide exposure. A forum expert warned against this and advised calling a qualified technician to repair the boiler. Treat any bypass as hazardous and stop using the boiler until fixed. [Elektroda, Piotr2608, post #16791369]
Does room ventilation or door grilles affect this model’s Error 11?
This EOLO is a closed-chamber, turbo boiler. It takes combustion air from outside via the concentric flue system. Room grilles and bathroom airflow do not drive combustion here. Focus checks on the outdoor air intake and the flue path instead of indoor vents. “Eolo is a boiler with a closed turbo chamber.” [Elektroda, irus.m, post #16793106]
What usually causes Error 11 on this boiler?
Typical culprits: blocked flue or outdoor air intake, leakage in the coaxial ducts, weak fan pressure, or a misadjusted or failed pressure switch. Start by confirming the flue and intake are clear and the system is airtight. If clear, test the switch and fan performance next. [Elektroda, irus.m, post #16793106]
What fixed the issue for the original poster?
Replacing the exhaust pressure switch resolved the fault. The boiler then ran without Error 11. As the owner reported: “Replacement of the exhaust pressure switch helped.” This directly links the remedy to restored operation in that case. [Elektroda, omaxp, post #17267860]
How much did the pressure switch repair cost in the thread?
The reported spend was PLN 200 for the pressure switch and PLN 100 for labor. Use this as a historical benchmark; local prices vary. The cost reference came later from the same owner who confirmed the fix. [Elektroda, omaxp, post #19979162]
Can I do anything myself before calling service?
Yes, basic non-invasive checks only: 1) Inspect the outdoor air intake and flue terminal for obstructions or debris. 2) Check visible flue joints for looseness or damage. 3) Restore the top cap and do not run with it open. If faults persist, call a technician. [Elektroda, irus.m, post #16793106]
Could a weak or failing fan trigger Error 11?
Yes. A degraded fan can produce insufficient differential pressure, preventing the pressure switch from changing state. An experienced member noted fan motors can lose parameters over time, triggering the fault path. A technician can test fan speed and pressure. [Elektroda, irus.m, post #16793106]
Should I add bathroom door vents or grilles to fix Error 11?
No, not for this model’s combustion. The EOLO draws air from outside, so indoor bathroom vents do not resolve a combustion-air Error 11. Focus on the concentric flue and air intake condition and component testing. [Elektroda, irus.m, post #16793106]
What is the exhaust pressure switch (presostat) on this boiler?
It is a safety sensor that verifies fan-driven airflow through the sealed combustion path. If it does not switch, ignition is blocked. In this thread, replacing it restored normal operation, confirming it as the failed part. “Replacement of the exhaust pressure switch helped.” [Elektroda, omaxp, post #17267860]
How old was the boiler when the problem appeared? Does age matter?
The owner reported the boiler was 5 years old and serviced. Faults can still emerge due to wear, debris, or component drift. Age is one factor, but diagnostics must verify airflow, fan, and the pressure switch. This case shows mid-life failures can occur. [Elektroda, omaxp, post #16791551]
Who should I call—gas utility or a boiler service technician?
Call a qualified boiler service technician. A member clarified that an appointment with a boiler serviceman is the appropriate route for this issue, not the gas utility. You need appliance-specific diagnostics and parts. [Elektroda, kasprzyk, post #16802979]
What happens if I ignore Error 11 or keep resetting it?
The boiler will continue to lock out to protect you. Forcing operation by opening the cap introduces serious safety risks, including carbon monoxide. Keep the cap installed and stop using workarounds. “This cap should be screwed on.” [Elektroda, Piotr2608, post #16791369]
How does a technician verify the pressure switch?
They measure the switch’s changeover pressure while the fan runs, compare to spec, and check tubing integrity. One expert noted failures are uncommon for this model, so they also assess fan performance and flue blockage during testing. [Elektroda, irus.m, post #16793106]
