Top boiler installer? Get listed for free

Worcester Greenstar i fault codes: What they are and what they mean

Heating Advice

Worcester are well regarded for their quality and their Greenstar i is combi boiler favourite amongst UK home owners. Very rarely though, there can be problems. Here is a list of potential error/fault codes and the action you'll need to take.

Before you panic that you're going to be out of pocket, consider two things.

1. Worcester Greenstar i's have excellent, long warranties - check if yours is still covered

Worcester Bosch have excellent warranties, very often stretching to a huge 10-years. Dig out your paperwork or check your emails to find out how long your warranty was and if it's still covered. The Greenstar i is Worcester's most popular combi boiler because it's efficiency and excellent reputation so there's a good chance yours will still be covered by the manufacturer warranty.

Remember that you will likely have had to keep up your annual boiler service appointments to uphold the warranty - your boiler warranty paperwork will detail this.

All of the below error codes are issues with the boiler itself, so if it's been installed by a legitimate Gas Safe heating engineer and you've had it serviced once a year, then Worcester will send an engineer out to get the issue resolved at no cost.

Compare quotes for a new Worcester Bosch Greenstar i below:

Compare Boiler Quotes

Which type of fuel heats your home?

2. Try resetting the boiler first

The old cliché of 'turn it off and on again' really can work sometimes. It's not that this will actually mend any genuine issues with the boiler, but sometimes an error code can be shown in, well, error. If this has happened and there isn't a genuine mechanical problem then a reset should make the boiler realise it shouldn't be displaying an error code and continue to function as normal after starting up again.

In order to reset your Worcester Greenstar i - press and hold either the 'reset' or '' button for approximately 8 seconds or until you can clearly see that the system has rebooted. If it's been effective, the word 'reset' will appear on screen before returning to the default menu. The boiler will now be restored to its factory settings so if you had any bespoke settings in use, you'll need to apply these again.

Worcester Bosch Greenstar i Error/Fault codes

Fault code Description Heating engineer required initially? Potential repair cost range
FD Power interrupted No - refer to manual & reset £0-£100
C7 Fan not running on start-up Yes £100-£300
C6 Fan speed too high or too low Yes £100-£300
C1 Fan stopping during operation Yes £100-£300
C4 Fan has failed to stop Yes £100-£300
E2 Flow temperature issue Yes £60-£100
E9 Primary flow temperature exceeding 95° Yes £60-£100
FA Ionisation detected after gas valve closed Yes £100-£250
EA No ionisation detected after ignition Yes £100-£140
F7 Ionisation detected before burner start Yes £100-£250
9U Control box defective or loose Yes £200-£300
C4 Control box or heat control module defective Yes £200-£300
F0 Gas valve/control box error Yes £250-£320
A8 Heat control module invalid Yes £100-£150
CC Outdoor sensor defect Yes £200-£250
A7 Domestic hot water sensor defect Yes £90-£150
A1 Pump stuck or running dry Yes £200-£300
E9 Flue or high limit thermostat activated Yes £100-£150
D4 Primary flow temps rising too fast Yes £200-£300


Read More

Buying Boilers,
Better Beyond Belief.

  • Instant prices from the UK's best installers
  • Compare deals without the pushy salesman
  • No stress, trouble, or obligation

Related Advice

Here's some more posts which we think you'll love

Boiler Brands
  • Made with by Heatable ©