Glow-worm Boiler Fault Codes | Wokinghams Local Expert
Seeing a strange error code on your Glow-worm boiler? Don’t panic — many problems can be resolved quickly, and some even without needing a heating engineer. Whether you’re in Wokingham, Earley, Woodley, or Shinfield, we’ve got you covered.
At Thermo-Tec Plumbing & Heating, we help local homeowners get their heating and hot water back on fast. Here's everything you need to know about Glow-worm fault codes, resets, and when to call in help.
Glow-worm Boiler Fault Codes Explained
Glow-worm boilers like the Betacom, Energy, and Ultimate models all use a fault code system to signal what’s wrong. Here are the most common ones we encounter:
F1 – Low Water Pressure
What it means: The system doesn’t have enough water pressure to operate safely.
Causes:
Bleeding radiators
Leaking pipework
Faulty pressure sensor or expansion vessel
DIY Fix:
Check the pressure gauge (should be 1.0–1.5 bar)
Re-pressurise using the filling loop
Reset the boiler
💡 If this keeps happening, get a heating engineer to check for slow leaks or valve issues.
F28 / F29 – Ignition Fault or Flame Loss
What it means: Your boiler can’t light or the flame has gone out.
Causes:
Frozen condensate pipe (in cold weather)
Faulty flame sensor
Air in gas supply
Blocked flue
What to try:
Check gas supply is active
Inspect outdoor pipes for freezing
Press the reset button
If these errors return, your ignition unit or sensor may need replacing.
F75 – Pressure Sensor / Pump Fault
What it means: The boiler isn’t detecting a pressure rise when the pump runs.
Causes:
Faulty pump
Blocked or broken pressure sensor
Air in the system
Fix: Needs a Gas Safe engineer. We'll test the sensor and pump and flush out trapped air if needed.
F22 – Dry Fire / No Water
What it means: The boiler is running with no water in the system.
Fix:
This is similar to F1 — check pressure and refill as needed. If it keeps returning, professional help is needed.
When to Call us your Local Gas Safe Engineer in Wokingham
If you're seeing recurring fault codes, unusual noises, smells, or a total system shutdown, it's time to call a qualified heating engineer.
At Thermo-Tec Plumbing & Heating, we’re Gas Safe registered and experienced with Vaillant fault codes. We cover Wokingham, Lower Earley, Woosehill, and surrounding villages.
Need a Glow Worm Boiler Repair in Wokingham?
If your Vaillant boiler is showing a fault code or refusing to fire up, we’re here to help.
Call Thermo-Tec today on 07850116944 for Glow Worm boiler repairs in Wokingham and surrounding areas.
FAQs – Glow-worm Faults
Q: Why does my Glow-worm keep losing pressure?
A: Likely a slow leak or faulty pressure vessel — we can investigate and repair it.
Q: Can I fix F28 or F29 errors myself?
A: You can try a reset and check outdoor pipes in winter, but repeated errors mean a component needs replacing.
Q: How long do Glow-worm boilers last?
A: With regular maintenance, most models last 10–15 years.