Worcester Bosch EA Error: Causes and Fixes in Milton Keynes

EA has a habit of appearing on the coldest morning of the year. The boiler is silent, the display flashes EA, and there is no heating or hot water. It is one of the Worcester Bosch codes we are called to most through a Milton Keynes winter, and the good news is that it is well understood. Many EA faults are cleared without a part, and most of the rest are fixed in one visit.

This guide explains what EA means on a Greenstar, what usually causes it, the three checks you can safely do yourself, and when to stop and call a Gas Safe registered engineer.

What the EA code means

When a Greenstar starts, the fan runs up, the gas valve opens, the electrode sparks and a flame should establish at the burner. A flame sensor confirms it. EA means the boiler ran that sequence, tried several times, and never detected a flame, so it locked out rather than keep releasing gas. Depending on the model you may see EA on its own or with a sub-code such as 227 or 229, which Worcester's own error code list explains in more detail.

It is a safety lockout, not a sign the boiler is finished. Something in the ignition chain is not working, and until it is found the boiler will not run.

The usual causes, in the order we find them

• Gas supply. The emergency control valve at the meter is closed, a prepayment meter has run out, the supply was left off after a meter exchange or other work, or there is a wider problem in the street. If the hob will not light either, it is not the boiler.
• Frozen condensate pipe. The single most common winter cause across MK. The plastic pipe that drains acidic water from the boiler freezes where it runs outside, the boiler cannot drain, and it locks out. Gurgling from the boiler before the lockout is the giveaway.
• Worn electrode or flame sensor. A normal wear item on a Greenstar that is more than a few years old. The spark weakens, or the flame is there but the sensor cannot prove it. Often an intermittent EA that becomes permanent.
• Fan. If the fan is not proving the right speed, the boiler will not allow ignition. Sometimes you hear it labouring or humming.
• Gas valve. A spark, no flame, and every other gas appliance is fine. The valve is not opening fully.
• PCB. The circuit board is not running the sequence correctly. Usually an EA with no pattern, often alongside other codes, more often on older Greenstar Si and CDi models.

Three safe checks before you call anyone

None of these involve the boiler casing or any gas fitting. Anything beyond them is a Gas Safe registered engineer's job by law.

• Check the gas supply. Try the hob or gas fire. If nothing gas-powered works, check the emergency control valve at the meter is open: lever in line with the pipe, not across it. Check a prepayment meter has credit. If you have had any work on the supply recently, it may simply have been left off.
• Check for a frozen condensate pipe. Follow the white or grey plastic pipe from the bottom of the boiler to where it goes outside. If it is freezing out and the exposed section feels solid, pour hand-warm water along it, never boiling, concentrating on bends, vertical drops and where it leaves the wall. A hot water bottle wrapped in a cloth works too. Once thawed, reset.
• Reset, up to three times. Hold the reset button for a few seconds and let the boiler try. If it lights and stays lit, the EA was a passing glitch, perhaps a brief dip in supply. If it comes back after three attempts, stop. More resets will not fix it and can hide the real fault.

If you smell gas at any point, leave the property, do not touch light switches, and call the National Gas Emergency Service on 0800 111 999.

When to call an engineer

• Three resets have not cleared it
• You have thawed the condensate pipe and EA still shows
• Other gas appliances work but the boiler will not light
• You can hear the boiler click and try to ignite with no flame
• EA keeps returning over days or weeks, even if a reset clears it each time

An engineer works through the chain in order: gas working pressure, condensate route and trap, electrode gap and lead, flame signal, fan, gas valve, then PCB. Worcester parts are well stocked at Milton Keynes merchants and the common wear items are on the van, so most EA calls are finished in one visit. Our boiler repair page explains how we diagnose first and agree the cost before touching anything.

What the repair will cost depends on

We do not print repair prices, because the same code can be a two-minute fix or a major part. What decides it: whether the cause is outside the boiler (supply, condensate) or a component inside; which component, since an electrode is a small part and a fan or PCB is not; the age and model of the boiler, because older ranges have dearer or scarcer parts; and whether it is in warranty. A reputable engineer tells you the call-out charge before setting off and the repair cost before starting.

Here is the honest bit: on a Greenstar that is twelve to fifteen years old, a PCB or fan replacement is often the moment to stop spending. We will tell you when that is the case rather than fit an expensive part to a boiler with a couple of winters left. Our repair or replace guide sets out how we make that call.

Stopping EA coming back

• Insulate the condensate pipe. Foam lagging on the external run, or rerouting to an internal drain, prevents most winter lockouts. Worcester's installation instructions also permit a larger bore external pipe for the same reason.
• Keep the heating ticking over in a cold snap. A low overnight setting keeps warm condensate moving.
• Annual service. The electrode, flame sensor, fan and condensate trap are all checked and cleaned. It also keeps the Worcester warranty valid. See our boiler servicing page.
• Do not ignore an occasional EA. A lockout every couple of weeks is a component telling you it is on its way out. Replacing it in autumn is cheaper and warmer than losing heating in January.
• Clean system water. Sludge does not cause EA directly, but a boiler running hot and struggling because of a blocked heat exchanger is harder on every component. If radiators are cold at the bottom, ask about a powerflush.

For other Greenstar problems, our Worcester Bosch repair page covers the codes we see most.

Frequently asked questions

Can I reset my Worcester Bosch boiler when it shows EA?
Yes. Hold reset for a few seconds and let it try. Up to three times. If EA returns after the third attempt there is an underlying fault and you need an engineer.

Is the EA fault dangerous?
The lockout itself is the safe outcome. It stops gas being released when a flame cannot be confirmed. The danger would come from bypassing it or opening the boiler yourself. If you smell gas, leave and call 0800 111 999.

Why does EA happen more in winter?
Because the most common cause is a frozen condensate pipe. Thaw it with warm water, then insulate or reroute the outside run so it does not happen again.

Will the warranty cover an EA repair?
If the boiler is within its Worcester Bosch warranty and has been serviced every year, component failures such as the electrode, fan, gas valve or PCB are normally covered. A frozen condensate pipe is not a defect and will not be. Check your registration paperwork and the servicing condition before you assume.

How long does an EA repair take?
Usually a single visit. Diagnosis is a methodical walk through the ignition chain, and replacing the common parts is quick. Only a rarer PCB or fan on an older model occasionally needs a part ordered.

Worcester Bosch repairs in Milton Keynes

We are a Worcester Bosch Accredited Installer and repair Greenstar boilers across Milton Keynes, including Bletchley, Newport Pagnell and Wolverton. If yours is stuck on EA after the checks above, get in touch or call 07805 844 016.