Worcester Boiler Fault Codes: EA 227, Flashing Blue Light and More

Updated July 2026 · Emergency Plumber Chelsea

Worcester boilers show faults as a two-character display code followed by a three-digit cause code, for example EA then 227. The letters tell you the family of fault and the number narrows it down. Always write both down before you press anything, because a reset clears the display and the engineer loses the most useful clue they have. Codes and their exact meaning can vary between generations of Greenstar, so treat this guide as a starting point and check it against the manual for your model, which is usually printed on a label under the front cover or on the data plate. Other makes use their own systems, and our guide to Viessmann boiler fault codes covers the Vitodens range.

EA 227 is one of the most common Worcester codes. It means no flame was detected during ignition. The boiler opened the gas valve, sparked, and the flame sensor did not confirm a flame, so it shut the gas off and locked out. First check whether other gas appliances work. If the hob will not light either, the problem is the gas supply, not the boiler: on a prepayment meter check the credit, and make sure the valve at the meter has not been knocked off. If gas is fine elsewhere, the next suspect in cold weather is the condensate pipe. When the plastic pipe that carries acidic water away from the boiler freezes or blocks, water backs up inside and the burner cannot run, and EA 227 is a typical result. Our frozen condensate pipe guide explains how to thaw one safely with warm, not boiling, water.

If the gas is on, the weather is mild and EA 227 keeps coming back after a reset, the cause is usually inside the boiler. A worn or badly positioned ignition electrode, a failing flame sensor lead, a gas valve that is not opening properly or a problem with the flue or air intake are all common. None of these are DIY jobs. They involve the gas train and the combustion side of the boiler, and by law only a Gas Safe registered engineer can open that up. Our boiler repair service handles these faults across Chelsea, Knightsbridge, South Kensington and Fulham.

CE 207 means the system water pressure is too low. The boiler will not run below a minimum pressure because the pump and heat exchanger need water to circulate. Look at the pressure gauge on the front or underneath: with the heating cold it should normally sit somewhere around 1 to 1.5 bar. If it has dropped towards zero, you can top it up through the filling loop, following the steps in your manual. A single top-up is normal maintenance. Needing to top up every week or so means water is escaping somewhere, and our guide to why a boiler keeps losing pressure walks through the usual culprits.

E9 224 means the safety temperature limiter has tripped, which is the boiler protecting itself from overheating. It usually points to poor circulation: a pump that has stuck or failed, sludge restricting flow through the heat exchanger, radiator valves that have all been turned off, or an airlocked system. Resetting once is reasonable. If it trips again, do not keep resetting it, because the boiler is telling you water is not moving through it properly. A heating engineer will check the pump, the flow through the system and, if sludge is the problem, whether the system needs cleaning.

A flashing blue light is how many older Greenstar models, such as the Greenstar Si and i Junior, signal a lockout. The display will normally show a code alongside it, so read the code first. On most models you then press and hold the reset button for a few seconds and wait while the boiler runs through its start-up sequence. If the blue light stops flashing and the boiler fires, keep an eye on it over the next day. If it goes straight back to flashing, the fault is still there and repeated resets will not fix it.

Worcester boilers with no hot water but working heating are another common call. On a combi, hot water depends on a diverter valve switching the heat from the radiators to the taps, and on a flow sensor that tells the boiler you have opened a tap. If either sticks, you get heating but lukewarm or cold taps. Hard London water also scales up the plate heat exchanger inside a combi over time, which slowly reduces hot water temperature and flow. If there is no fault code at all, check the hot water temperature setting, and whether any other taps in the property give hot water, before booking a visit. Our no hot water guide covers the wider checks. Our guide to a Worcester boiler with no hot water goes through those checks step by step.

There are a few things you should never do with any Worcester fault. Do not remove the front casing to look inside, do not bang the boiler or the pipes to free a stuck part, and do not keep pressing reset over and over. Most boilers will only accept a limited number of resets before a longer lockout, and every failed ignition attempt is gas being released and not burned. If you ever smell gas, leave the property, do not use switches, and call the National Gas Emergency Service on 0800 111 999 from outside. For suspected gas escapes we also offer gas leak detection once the network has made the supply safe.

Many Worcester faults are prevented by an annual service. The engineer cleans and checks the electrode, the condensate trap and siphon, the burner and the flue, and checks the expansion vessel charge so the pressure stays stable. A boiler that has missed a few services is more likely to throw EA 227 on the first cold morning of winter. Our boiler service in SW3 and SW10 includes those checks, and it is also a good time to ask whether an older Greenstar is approaching the point where replacement makes more sense.

If your Worcester boiler is showing a code you cannot clear, or it keeps locking out, call Emergency Plumber Chelsea on 020 3002 6667. Tell us the display code, the cause code, the model and whether you have gas at the hob, and we can often narrow the fault down on the phone before an engineer arrives. We cover Chelsea, Knightsbridge, Sloane Square, South Kensington and Fulham, and there is no call-out fee on jobs over 3 hours.

Quick tips

• Write down both parts of the code, for example EA and 227, before you press reset.
• EA 227 plus no gas at the hob is a gas supply problem; check the meter and prepayment credit first.
• In a cold snap, EA 227 often means a frozen condensate pipe; thaw it with warm water, never boiling.
• CE 207 is low pressure; top up to around 1 to 1.5 bar cold, and book a check if it keeps dropping.
• Reset once or twice at most; a code that returns straight away needs a Gas Safe engineer, not more resets.

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