Troubleshoot Worcester Boiler Fault 227: Causes & Fixes

Lee Devlin, Director of Homecure Plumbers

By Lee Devlin, Director, Homecure Plumbers
Last updated 13 October 2026

Worcester Bosch fault EA 227 means the boiler tried to light but could not detect a flame, so it locked out for safety. First check that your gas supply is on and has credit, and thaw the condensate pipe if it is frozen, then reset the boiler once. If it locks out again, the cause is inside the boiler and needs a Gas Safe engineer.

EA 227 shows on the Greenstar range. For other Worcester codes, see our Worcester Bosch problems and fault codes guide.

What you can check yourself

Check the gas is getting through. Try the hob or another gas appliance. If that does not work either, the problem is your gas supply, not the boiler.
Check prepayment meter credit if you have one.
Check the condensate pipe in cold weather. If it is frozen, pour warm (not boiling) water along the outside section of the plastic condensate pipe, or hold a hot water bottle against it, then reset the boiler.
Reset the boiler once using the reset button. Check your manual for your model.

If the boiler locks out with EA 227 again, stop resetting it and book an engineer. If the condensate pipe keeps freezing, an engineer can often reroute it inside to a waste pipe, so there is no outside run left to freeze.

Condensate pipe run along an outside wall that has frozen — A condensate pipe run outside that froze. Long, exposed runs like this are the usual cause of EA 227 in winter.

Old and new boiler electrodes side by side — Worn electrodes next to new ones. A worn flame sensing electrode can cause EA 227 even in mild weather.

Safe for you to try

Checking other gas appliances and prepayment meter credit.
Thawing a frozen condensate pipe with warm water.
Resetting the boiler once.

Gas Safe engineer only

Checking or replacing the gas valve.
Testing the gas pressure at the boiler or the meter.
Cleaning or replacing the ignition electrode or flame sensing electrode.
Checking the ignition lead, fan, flue and control board.
Renewing the burner gasket and carrying out a full flue gas combustion check whenever the combustion seal is disturbed.
Anything inside the boiler casing.

Always check your engineer is on the Gas Safe Register.

If you smell gas, do not reset the boiler. Turn off the gas at the meter if you can, open the windows, do not use switches or naked flames, leave the property and call the National Gas Emergency Service on 0800 111 999.

What causes EA 227

Cause	Who fixes it
Gas supply off, or no prepayment meter credit	You, or your gas supplier if other appliances are also off.
Frozen or blocked condensate pipe	You can thaw a frozen pipe. A blocked pipe inside the boiler is engineer only.
Worn or dirty ignition or flame sensing electrode	Gas Safe engineer only.
Faulty gas valve or low gas pressure	Gas Safe engineer only.
Fan, flue or control board fault	Gas Safe engineer only.

In milder weather, EA 227 can also be caused by the boiler’s internal plastic siphon trap becoming clogged with aluminium deposits from the heat exchanger, requiring a Gas Safe engineer to remove and flush it.

Recent EA 227 jobs

From the job: Greenstar 30i, EA 227 every cold snap

Greenstar 30i, same fault (EA 227) recurring in cold weather. Thawing the condensate pipe got it going each time. Rerouted the condensate inside to the waste under the kitchen sink. No outside run means nothing left to freeze.

Expert notes by Jamie Watkins, Gas Safe registered engineer (Gas Safe ID 6115118), Homecure Plumbers – Gas Safe Reg 505421

From the job: Greenstar 25i, EA 227 in mild weather

Greenstar 25i locking out on EA 227 even in mild weather. The flame sensing electrode was worn and pitted. Fitted a new one with a new gasket and checked the combustion afterwards. Total for the job: £232 + VAT.

Expert notes by Jamie Watkins, Gas Safe registered engineer (Gas Safe ID 6115118), Homecure Plumbers – Gas Safe Reg 505421

What an EA 227 repair costs

Repairs from £95 + VAT for the first hour, including diagnosis (or a fix if it can be done within the first hour with no parts needed), no callout charge.

Typical costs, fitted: flame sensor and gasket replacement from £232 + VAT; electrode replacement from £198 + VAT; gas valve replacement from £288 + VAT. Subject to diagnosis; prices vary depending on boiler model and job complexity. Prices apply during office hours; parking or the congestion charge may be added.

Book a Worcester boiler repair or call 0203 504 4000.

Questions about EA 227

Can I keep resetting my boiler?

No. One reset after you have checked the gas and condensate pipe is fine. Repeated resets on an ignition fault are unsafe, so book an engineer.

Why does EA 227 happen more in winter?

The condensate pipe outside can freeze, which backs water up into the boiler and stops it lighting.

Sources: Worcester Bosch: manuals · Gas Safe Register

How to Troubleshoot Worcester Boiler Fault 227: Causes & Fixes