Baxi Boiler Fault Codes: E1, E133, E119 and What to Do

Updated July 2026 · Emergency Plumber Chelsea

Baxi boilers report problems with an E followed by a number, and on most current models the number is three digits: E110, E119, E133 and so on. Older or smaller displays cannot show three digits at once, so they flash the code in two parts. If you see E1, then a pause, then 33, you are looking at E133, not a separate E1 fault. Take a photo or short video of the display before you do anything else. It saves guesswork later and is the first thing an engineer will ask for. Codes and their meanings can differ between Baxi generations (the 200, 400, 600 and 800 ranges, EcoBlue, Platinum, Duo-tec and the older Combi and Main models), so check your model's manual too, which is usually tucked behind the front flap or available from Baxi online.

E133 is an ignition or gas supply fault. The boiler has tried to light, has not detected a flame, and has shut down for safety. Start with the easy checks. Is the hob working? If not, the problem is the gas supply to the property rather than the boiler. If you are on a prepayment meter, check the credit and the emergency credit. Check that the gas isolation valve under the boiler has not been knocked half closed, usually a yellow-handled lever that should sit in line with the pipe. If all of that is fine and the weather is cold, look at the condensate pipe next.

A frozen condensate pipe is the single most common cause of E133 in winter. Modern condensing boilers produce water as they run and drain it through a thin plastic pipe, often to an outside gully. When that pipe freezes, condensate backs up inside the boiler and it refuses to fire. You may hear a gurgling from the boiler before the fault appears. Pour warm water, not boiling, slowly along the outside section of the pipe, especially at bends and the open end, then reset. Our frozen condensate pipe guide walks through it step by step, including where the pipe usually runs in Chelsea terraces and mansion flats.

To reset most Baxi boilers, press and hold the reset button for a few seconds. It is usually marked with an R or a flame with a cross through it. On some models you turn the mode selector to the reset position instead. Give it a minute to run through its start-up sequence. If it lights and keeps running, keep an eye on it for the rest of the day. If it goes straight back to E133, do not keep resetting. Each failed ignition releases a little unburned gas, and repeated attempts can push the boiler into a longer lockout. At that point the fault is inside the boiler, typically a worn ignition or flame sensing electrode, a gas valve fault or a blocked flue or air intake, and it needs a Gas Safe engineer. Our guide to resetting a boiler safely explains when a reset is the right move and when it is not.

E118 and E119 are pressure codes. E118 generally means the primary water pressure is too low for the boiler to run, and E119 that the pressure switch has not detected enough pressure. Check the gauge on the front of the boiler. With the heating cold, most Baxi combis want roughly 1 to 1.5 bar. If it has fallen below that, top it up with the filling loop underneath the boiler, following the manual, opening the valves slowly and closing them firmly when the gauge is in range. The code should clear. Do not overfill; if you push it to 2.5 bar cold, it will climb further once hot and the pressure relief valve may open. If you have gone too high, see our guide on boiler pressure that is too high.

The important question with E118 and E119 is why the pressure fell. Topping up once after bleeding radiators is normal. Needing to top up every week is not. Water is leaving the system somewhere: a weeping radiator valve, a leak under the floorboards, the pressure relief valve letting by through the copper pipe on the outside wall, or a failed expansion vessel that makes the pressure swing up and down. Our guide on why a boiler keeps losing pressure covers each cause and how to spot it, and a hidden leak in a solid floor or ceiling void is exactly the sort of thing our leak detection service finds without lifting half a room.

A handful of other Baxi codes come up regularly. E110 is usually an overheat or safety thermostat trip, which often points to poor circulation from a sticking pump, closed valves or sludge in the system. E125 is generally a circulation fault, again pointing to the pump or a blockage. E160 is typically a fan fault, and E20, E28 and E50 are sensor or thermistor faults on the heating, flue or hot water side. E168 is reported on a number of Baxi models as an ignition or flame detection fault and is treated much like E133. None of these can be fixed with a top-up or a reset. The boiler has found a component that is not behaving and it needs testing with the right equipment.

If you are not sure whether you have a Baxi, check the badge. Main and Potterton boilers come from the same group and some models use similar codes, but always check against that model's manual. Other brands use their own systems entirely. Our Worcester fault code guide covers EA 227 and the flashing blue light, and our Ideal fault code guide covers F1, F2 and L2.

Some things are never worth attempting. Do not remove the boiler casing, do not try to clean or bend the electrode, and do not bypass or tape over anything. The sealed combustion chamber is sealed for a reason. If you smell gas at any point, stop, leave the property without using switches, and call the National Gas Emergency Service on 0800 111 999 from outside. Gas work on the appliance itself must be done by a Gas Safe registered engineer.

Most Baxi faults we see in Chelsea have ordinary causes: electrodes that have worn after years without a service, condensate traps that have never been cleaned, sludge in older radiator circuits in period houses, and expansion vessels that have lost their charge. An annual boiler service catches most of these before the first cold snap. When a fault does happen, our boiler repair service sends Gas Safe registered engineers across SW3, SW10, Knightsbridge, South Kensington, Sloane Square and Fulham. Call Emergency Plumber Chelsea on 020 3002 6667 with the fault code and the boiler model, and we will tell you whether it is something you can safely check yourself first. There is no call-out fee on jobs over 3 hours.

Quick tips

• If the display shows E1, watch for a second number; E1 then 33 is E133.
• For E133, check the hob, the prepayment meter and the condensate pipe before resetting.
• Thaw a frozen condensate pipe with warm water, never boiling.
• For E118 or E119, top up to around 1 to 1.5 bar cold, and find out why it dropped.
• One reset is fine; if the same code returns straight away, stop and book a Gas Safe engineer.

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