Common problems guide

The most common Glow-worm Energy7 Regular problems

The faults most likely to send a Glow-worm Energy7 Regular into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

35 documented codes
6 most common
0 DIY-safe checks
6 engineer needed

The 6 most common faults

01
F.00 High Engineer

Your boiler has lost the ability to accurately measure the temperature of the water flowing through it, so it has shut down to prevent overheating.

Est. cost
£120-220
Parts
Flow temperature sensor, Wiring harness
Full guide for F.00
02
F.10 High Engineer

Your boiler has detected an electrical fault with the sensor that measures the temperature of the water circulating through your heating system, so it has shut down as a precaution to prevent overheating.

Est. cost
£120-220
Parts
Flow temperature sensor (NTC thermistor), Wiring harness
Full guide for F.10
03
F.11 High Engineer

Your boiler has detected an electrical fault in a sensor that monitors the water returning to the system, causing it to shut down for safety.

Est. cost
£120-220
Parts
Return NTC thermistor
Full guide for F.11
04
F.20 High Engineer

Your boiler has switched itself off because it has detected that it is running much hotter than it should be.

Est. cost
£150-300
Parts
NTC Sensor, Pump, PCB
Full guide for F.20
05
F.23 High Engineer

Your boiler has detected that the water inside is not circulating properly, causing an abnormal difference in temperature readings between two sensors.

Est. cost
£150-350
Parts
Central heating pump, NTC thermistor sensors, Heat exchanger
Full guide for F.23
06
F.24 High Engineer

Your boiler has detected that the water temperature is rising too quickly, so it has safely shut itself down to prevent any damage.

Est. cost
£150-300
Parts
Pump, System filter, Heat exchanger
Full guide for F.24
Parts most often replaced

on the Glow-worm Energy7 Regular

Flow temperature sensorWiring harnessFlow temperature sensor (NTC thermistor)Return NTC thermistorNTC SensorPump

Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.

Call a Gas Safe engineer if…

  • You can smell gas or see signs of a leak
  • The Glow-worm shows an Emergency or High severity code
  • The boiler keeps locking out after repeated resets
  • You've tried the DIY checks and the fault hasn't cleared
  • There's visible water leaking from the boiler
  • The flame is yellow or orange instead of blue
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See the full 35-code list for the Glow-worm Energy7 Regular

Related guides

Boiler losing pressure → No hot water → When to replace → Symptom checker →