Baxi Boiler Flashing Red Light

What does the flashing red light on my Baxi boiler mean?

On a Baxi, the red light is the lockout light: it tells you the boiler has put itself into lockout. Lockout is a safety state. The boiler has seen something it does not like, closed its gas valve and will stay off until someone resets it. It is not the same as a boiler that is simply switched off or waiting for the timer.

Which fault caused the lockout depends on the model. On boilers with a digital display, such as the Baxi 600 and 800 series combis, the display shows an E code alongside or instead of the light, and the code is the thing to read. E133, which a two-character display shows as an E1 code followed by 33, is the usual ignition fault, and low water pressure shows as E118 or Baxi E119. The Baxi 200 and 400 use E04 10 for ignition and E02 07 for low pressure. On older Baxi boilers with a row of small neon lights and no screen, which neon is lit, steady or flashing, tells you the fault.

The Baxi Combi 80e and 105e are a good example. The user guide gives each fault its own neon in the row of temperature neons: lit steady, a neon shows the water temperature, and flashing, it shows a fault:

• Red flame failure neon: the burner failed to light, or lit incompletely. Reset by turning the selector fully anticlockwise, against the spring, to R and releasing it.
• Safety thermostat neon: the boiler or the system overheated and the safety device shut it down. It resets the same way.
• Air flow neon: the flue or flue terminal is blocked or obstructed, or there is an internal fault.
• Pump or low pressure neon: the pump is faulty or the system pressure has dropped below the minimum.
• Sensor fault neons: a fault on the hot water or central heating temperature sensor.

The layout differs between models. If your boiler has a screen, go by the code on the screen, and check the user guide for your model before you assume what a light means. Baxi’s own warning on the 80e is that a flame failure neon which lights repeatedly means a fault, and an engineer should be called.

Why is the flame failure light flashing?

Because the red light is most often the flame failure light, it helps to know why a Baxi fails to light. Work down this list in order. The first three are things you can check without touching the boiler. The rest are parts inside the casing.

• No gas reaching the boiler: a prepayment meter out of credit, an emergency control valve by the meter knocked off, or a supply problem in the street. Try the hob. If the hob will not light either, the boiler is not the problem.
• A frozen or blocked condensate pipe: on a condensing Baxi the plastic pipe that carries waste water to a drain can freeze in a cold snap. The boiler backs up and locks out, often with a gurgling sound first.
• Low system pressure: on display models this shows as E118 or E119 rather than a red flame fault, and on the 80e it has its own neon, but check the gauge while you are there. It should read about 1 to 1.5 bar cold on most modern Baxi combis.
• A worn or dirty ignition electrode, or a cracked electrode lead, which stops the spark or the flame sensing.
• A faulty gas valve or a fault on the printed circuit board.
• A fan or flue problem that stops the boiler proving it has enough air to burn safely.

How to reset a Baxi boiler showing a red light

Baxi fits three kinds of reset control, and the right one depends on the age of the boiler. Baxi’s own guidance is that a boiler which locks out frequently has a fault and needs an engineer, so reset once, perhaps twice, not over and over. For the full walkthrough by model, see our guide on how to reset a Baxi boiler.

• Reset button: press it until the red light goes out. The burner light should come on when the boiler next calls for heat.
• Selector switch with an R position: turn it anticlockwise to R, hold it there for about five seconds, release, then set it back to heating and hot water.
• Temperature knob reset: on some models you turn the heating temperature knob fully anticlockwise and hold it until the red light goes out, then turn it back to your setting.
• After the reset, run a hot tap or turn the heating up and wait two or three minutes. If the fault is still there, the boiler will lock out again within that time.

Never take the front casing off to look for the problem. Everything behind it is gas work. If you smell gas at any point, stop, open the windows, turn the gas off at the meter if you can reach it safely, keep away from switches and flames, then leave the property and call the National Gas Emergency Service on 0800 111 999.

The red light keeps coming back: what now?

If the light returns within minutes of a reset, or the boiler runs for a day and then locks out again, the lockout is doing its job. Something is stopping a clean, safe ignition, and pressing reset a dozen times will not fix it. Each failed attempt also puts more wear on the ignition electrode and the gas valve, which is one reason manufacturers tell you to stop resetting and call someone.

Before you call someone, spend two minutes on these checks. They either solve it or give the engineer useful information.

• Is the hob or gas fire working? If not, call your gas supplier or the emergency number, not a boiler engineer.
• On a prepayment meter, check the credit and the emergency credit, then top up and wait a few minutes before resetting.
• Look at the pressure gauge. Below 1 bar cold, top up with the filling loop, as covered in our Baxi boiler pressure guide.
• In freezing weather, follow the white or grey plastic condensate pipe outside and look for ice. Warm water poured over the frozen section, never boiling, usually clears it.
• Note which light flashes, or which code shows, and how long the boiler ran before it locked out.

What the engineer does and what it typically costs

An engineer starts with the gas side. They check the working pressure at the gas valve with a manometer, because a boiler starved of gas behaves exactly like one with a failed part. Then they watch an ignition attempt with the case off: whether the spark is there, whether the flame lights and drops out, and what the fan does. That usually narrows it to one part within the first visit.

The common repairs on a Baxi that keeps locking out, with typical market prices for parts and fitting across the UK, are:

• Ignition or flame sensing electrode: often around £80 to £200 fitted
• Condensate pipe rerouted or lagged so it stops freezing: often £100 to £250
• Fan: often £200 to £350 fitted
• Gas valve: often £200 to £400 fitted
• Printed circuit board: often £350 to £700 fitted, depending on the model

These are typical market ranges, not our prices. With us you pay the £60 call-out, and the repair price is agreed with you on site before any work starts. Gas work is carried out by Gas Safe registered engineers.

Can I leave a Baxi boiler with a red light until morning?

Usually yes, as long as there is no smell of gas and no water coming out of the boiler. A locked-out boiler is safe, because the gas valve is closed. The problem is comfort: no heating and, on a combi, no hot water.

It becomes more urgent when someone in the house is elderly, very young or unwell, when the weather is below freezing and the pipes are at risk, or when the red light sits alongside a leak or a dropping pressure gauge. If any of those apply, get someone out tonight through our emergency boiler repair service. If not, a Baxi boiler repair visit the next day is usually the sensible choice.