The Glow-worm Flexicom 30cx is a condensing combi boiler that displays a fault code whenever it detects a problem with ignition, pressure, temperature or airflow. Some codes clear with a simple check. Others need a Gas Safe registered engineer.
This guide covers the fault codes we're asked about most often on the Flexicom 30cx, what each one means, and when it's time to arrange a repair.
- Content Guide
- » What Is the Glow-worm Flexicom 30cx Boiler?
- » Common Glow-worm Flexicom 30cx Fault Codes
- - F1 – Ignition or Gas Supply Fault
- - F2 – Flame Detection Fault
- - F3 – Fan or Air Pressure Switch Fault
- - F5 – Overheating Fault
- - F22 – Low Water Pressure
- - F11 – Communication Fault
- - F71 – Temperature Sensor Fault
- » What Causes Glow-worm Flexicom 30cx Fault Codes?
- » Troubleshooting Glow-worm Flexicom 30cx Fault Codes
- » Looking After Your Glow-worm Flexicom 30cx
- » Glow-worm Boiler Repairs in London
- » Frequently Asked Questions
What Is the Glow-worm Flexicom 30cx Boiler?
The Flexicom 30cx is a wall-mounted combi boiler, providing both central heating and hot water from a single unit without a separate cylinder. Like other Glow-worm models, it displays fault codes on its front panel to help identify problems quickly.
If your boiler is showing a different error, our guide to Glow-worm boiler fault codes explains the most common Glow-worm error codes across the range.
Common Glow-worm Flexicom 30cx Fault Codes
F1 – Ignition or Gas Supply Fault
The boiler has failed to ignite. This usually points to an interrupted gas supply, a fault with the ignition components, or a frozen condensate pipe in cold weather.
F2 – Flame Detection Fault
The boiler lit but couldn't maintain or detect the flame afterwards. This can be caused by a dirty flame sensor, a faulty gas valve or wiring problems.
F3 – Fan or Air Pressure Switch Fault
The boiler can't confirm the fan or air pressure switch is working correctly, so it won't begin combustion. A blocked flue, a failing fan or a faulty switch are the usual causes.
F5 – Overheating Fault
The boiler has detected overheating, often linked to poor water circulation. A faulty pump, blocked pipework or a failed thermistor can all be behind it.
F22 – Low Water Pressure
System pressure has dropped too low for the boiler to operate safely. Topping up using the filling loop often clears this fault — if it keeps returning, there's likely a leak.
F11 – Communication Fault
The boiler has detected a communication problem, usually between the PCB and a sensor or the control panel. This needs testing by a Gas Safe engineer.
F71 – Temperature Sensor Fault
A flow or return temperature sensor is giving an inaccurate or missing reading. The boiler locks out rather than operate on unreliable data.
Common Glow-worm Flexicom 30cx Fault Codes
Most Flexicom 30cx faults trace back to a handful of underlying causes.
Low system pressure
Pressure naturally drops over time, and a leak will cause it to fall more quickly.
Frozen condensate pipe
In cold weather, the external condensate pipe can freeze and block, triggering a lockout.
Lack of servicing
Skipped services allow sludge, limescale and worn components to build up unnoticed.
Electrical supply problems
Power interruptions or a tripped breaker can stop the boiler operating correctly, sometimes without a clear fault code.
Gas supply problems
An interrupted or low gas supply prevents the burner from lighting or staying lit.
Troubleshooting Glow-worm Flexicom 30cx Fault Codes
Check boiler pressure
Confirm the gauge reads around 1 to 1.5 bar. Top up using the filling loop if it's low.
Inspect the condensate pipe
Look for ice on the external pipe during cold weather. Thaw gently with warm — not boiling — water if frozen.
Reset the boiler
Follow the manufacturer's reset procedure once. If the fault returns immediately, stop resetting and investigate further.
Check external causes
Confirm the gas and electrical supplies are on, and check other appliances are working normally.
When to call a Gas Safe engineer
If the fault won't clear after these checks, or keeps returning, arrange a Gas Safe engineer rather than continuing to reset the boiler. If these checks don't clear the fault or the boiler repeatedly locks out, it's time to arrange a professional boiler repair in London
Looking After Your Glow-worm Flexicom 30cx
Annual servicing
A yearly Gas Safe service identifies worn parts before they cause a breakdown.
Monthly checks
Glance at the pressure gauge each month, particularly during the heating season.
Winter preparation
Insulate the condensate pipe before cold weather sets in to reduce the risk of freezing.
Water quality
A magnetic filter and inhibitor help reduce sludge and limescale build-up over time.
Glow-worm Boiler Repairs in London
Serviceteam's Gas Safe engineers repair Glow-worm boilers, including the Flexicom 30cx, across London.
Still seeing a Glow-worm Flexicom 30cx fault code after carrying out the basic checks? Book a boiler repair and we'll diagnose the fault and get your heating working safely again.
Frequently Asked Questions
How do I reset a Flexicom 30cx?Follow the reset procedure in your boiler manual. If the same fault returns straight away, arrange a Gas Safe engineer rather than resetting repeatedly.
Why does my Flexicom 30cx keep losing pressure?Repeated pressure loss usually points to a leak somewhere in the system rather than something you need to keep topping up.
How often should a Flexicom 30cx be serviced?Once a year, by a Gas Safe registered engineer.
