Are you concerned about your faulty Worcester Bosch Greenstar boiler?

If you own a Worcester Bosch Greenstar, the chances are your boiler is probably under 10 years old, as most of these models were first introduced around 2004/2005.

As a heating engineer, I know it can be particularly stressful for my customers when their boiler is playing up – especially when you don’t know what’s wrong and how big a job it’ll be to fix.

To help you out, I’ve listed four of the most common problems myself and other engineers have found over the many years of working on faulty Worcester Bosch Greenstar boilers, below:

NOTE: This blog does NOT cover older Worcester models. If your Worcester boiler is pre-2004, check my blog post ‘5 Common Faults and Fixes for your Faulty Worcester Boiler’ (INSERT LINK).

Common fault 1: Low boiler pressure

The Cause: If you’re done all the usual checks (including checked the radiators for leaks and looked at the pressure relief valve without finding any faults), it could be the automatic air vent. You’ll be able to tell by taking off the plastic bottom panel and seeing if there is rusty water.

The Fix: This is usually just a case of dropping the pressure, pulling out the retaining quick release pin, and replacing the air vent. Then all we’d need to do is refill the system and test.

Common fault 2: EA error code

The Cause: This is by far the most common problem we’re called out to, and it’s caused by the condensate pipe becoming frozen or blocked. This is usually down to installer error rather than a fault with the boiler.

You can confirm it’s a problem with the condensate pipe by pressing the reset button and when the boiler fires up, it should make gurgling noises before cutting out again.

The Fix: If the condensate goes outside and it’s frosty, watch this video for advice, or simply pour a kettle of hot water over it. It may be the condensate trap is blocked and the boiler needs to be serviced.

Common fault 3: Boiler failing to ignite

The Cause: If your boiler refuses to ignite, and you can hear it going through the sequence before making a ticking noise (trying to ignite), it could be that the gas has been turned off or a fault in the ignition leads.

The Fix: Check there is gas coming into the house, as it may have been turned off outside. If you have a prepaid meter, check it is topped up. Alternatively, your ignition leads may need replaced or the boiler serviced.

Common fault 4: Strange banging noises

The Cause: If you hear a strange banging noise when your boiler fires up, this is usually a problem with the gas valve communicating with the fan speed.

The Fix: Call a Worcester Bosch service engineer or an accredited engineer, who will be able to take a look at it for you.

Call an experienced Worcester Bosch engineer

Worcester Bosch Greenstar boilers are very reliable, well-built boilers. However, if you do experience problems, I’d recommend either calling in a Worcester Bosch service engineer or Worcester Bosch accredited engineer.

It’s definitely better to call someone with specific product knowledge, rather than just going straight to your local gas engineer.


Sometimes there’s nothing worse than having to deal with boiler faults and error codes. If you have a faulty Worcester Bosch Greenstar boiler, follow my tips above for solving some of the most common faults these boilers experience. Including:

  • Low boiler pressure
  • EA error code
  • Boiler failing to ignite
  • Strange banging noises

Remember, if you’re in any doubt, call an experienced Worcester Bosch service engineer or accredited installer.

Good luck!