FAQ
TL;DR: For Worcester 24i RSF-L intermittent ignition, 3 likely culprits. "The problem may be in the pressure switch...or the venturi tube." Check the heat exchanger, too. Reset via the STB if fitted. [Elektroda, piracik, post #17389446]
Why it matters: This FAQ helps Worcester 24i RSF‑L owners and DIY caretakers triage no‑ignite/hot‑water issues fast and talk clearly with a technician.
Quick Facts
- The 24i RSF‑L lacks a digital display and error codes; diagnose by fan/spark/flame behavior. [Elektroda, roleczka0, post #17388941]
- Fan starts with hot‑water demand and spins briefly after the tap closes; note this baseline. [Elektroda, roleczka0, post #17388941]
- Typical failure points: fan pressure switch, venturi tube, and a dirty heat exchanger that impedes airflow proving. [Elektroda, piracik, post #17389446]
- Manual reset may be a push‑in STB on the top‑left on some variants; location varies by country build. [Elektroda, serwisszulborski.pl, post #20857167]
- Reported workaround: set heating to III and to 1 (not Auto) and reseat panel wiring to restore ignition temporarily. [Elektroda, roleczka0, post #18877247]
What causes intermittent spark on a Worcester 24i RSF‑L?
Three common culprits are cited: the fan pressure switch, the venturi tube, and a dirty heat exchanger. These issues interrupt air‑proving or flame start. Cleanliness and clear tubing matter. “The problem may be in the pressure switch...or the venturi tube.” Start checks there before replacing parts. [Elektroda, piracik, post #17389446]
Does the 24i RSF‑L show error codes or have a digital display?
No. This model has no electronic display, so you won’t see error codes. Diagnose by symptoms such as fan behavior, spark presence, and whether the flame lights. Note what changes when you open or close a hot tap. Record these observations for a technician. [Elektroda, roleczka0, post #17388941]
How should the fan behave when I open and close a hot tap?
Users report the fan starts when hot water is demanded. After closing the tap, it keeps spinning for a short time. That spin‑down period is expected on many fan‑assisted appliances. Use this as a baseline when checking airflow/pressure proving. [Elektroda, roleczka0, post #17388941]
How do I reset or restart ignition on a 24i RSF‑L?
If fitted, press the manual reset (STB) button. Some variants place a push‑in STB at the top‑left. Press once and wait for the boiler to restart its sequence. The exact location can differ by country assembly. [Elektroda, serwisszulborski.pl, post #20857167]
Where is the reset/STB button located on this boiler?
On certain 24i RSF‑L variants, the reset is a push‑in STB located at the top‑left. Other builds may place it differently. Look for a small manual reset near the controls or heat exchanger area. Position varies with country of assembly. [Elektroda, serwisszulborski.pl, post #20857167]
How can I quickly check the pressure switch or venturi path?
Start with basic, safe checks: 1) Isolate power/gas, remove the cover, and inspect the venturi/pressure switch tubing for splits or blockages. 2) Reseat electrical connectors and ensure hoses are snug on the fan and switch. 3) Restore power and run hot water to observe ignition. These focus on the cited fault path. [Elektroda, piracik, post #17389446]
Can control settings help hot‑water ignition if the spark is flaky?
Yes. A user restored ignition by setting heating to III and to 1 (not Auto). This ensured heating power was available during hot‑water calls. Use it as a temporary workaround while you fix the root cause. [Elektroda, roleczka0, post #18877247]
Could wiring harness or control‑panel connections cause intermittent sparking?
Yes. The OP reported the spark returned after moving or securing the internal cables. The boiler then worked for the season and failed again after winter. Reseating the wiring harness can temporarily restore ignition. [Elektroda, roleczka0, post #18877247]
Did anyone in this thread resolve the issue? What worked?
The OP improved reliability by setting heating to III and 1, then securing the panel wiring. Ignition stabilized for the rest of the season. After winter, the intermittent spark returned, indicating a recurring connection or control issue. [Elektroda, roleczka0, post #18877247]
Does a blocked flue/chimney affect ignition on this boiler?
Yes, airflow matters. A contributor asked about flue obstruction when diagnosing no‑spark. Many units vent through a wall in the UK. Confirm the flue path is unobstructed before diving deeper into components. [Elektroda, piracik, post #17388138]
The fan keeps running after I close the tap—should I worry?
Brief fan run‑on after hot‑water use has been observed by users. This behavior can occur as the unit completes a post‑demand cycle. If the fan runs constantly with no demand, that’s different and needs a check. [Elektroda, roleczka0, post #17388941]
Where can I find parts like a motherboard or donor 24i RSF‑L?
Owners search for spares and donor boards on forums and classifieds. Consider used parts from decommissioned units or local repair networks. Post your exact model and needs to improve match chances. [Elektroda, Dzaba17, post #19664985]
How do I ask for onsite help (e.g., in Pisz)?
Share your location, model (Worcester 24i RSF‑L), symptoms, and any photos. Ask for local service in your post title and body. Technicians nearby may respond or message you. [Elektroda, roleczka0, post #17392796]
