Baxi boiler error codes explained: E119, E133, E125, E110 and what to do
- Checked September 2026
- 5 min read
- By PROS AI editorial team
Quick answer
The short version, before the detail.
A Baxi error code names the safety check that stopped the boiler, and E133 is the common one: a gas supply, ignition or blocked condensate problem. E118 is water pressure below 0.5 bar, E125 a circulation fault, and E110 an overheat trip, usually because water is not moving. Baxi's own advice is that most codes need only a reset, and a homeowner may also check the gas, top up the pressure and thaw a frozen condensate pipe. Everything else is Gas Safe work.
What is the likely cause?
One code per item, most common first, in Baxi's own wording.
E133 (gas supply fault): Baxi's reset guide says E133 indicates "a problem with either the gas supply, ignition/flame or a blocked condensate".
In winter the blockage is usually ice on the outside pipe; Baxi says "E133 or E28" appear on most of its boilers when that happens. The one safe thing: check another gas appliance lights, top up a prepayment gas meter, thaw the condensate pipe if it is iced, then reset once.
E119: Baxi's own FAQ lists E119 with E28, E53, E133 and E128 as codes that can mean "your condensate pipe may be frozen".
On the ranges Baxi lists a low-pressure fault shows as E118, so if E119 is on your display check the gauge as well and follow the boiler's own user guide. The one safe thing: thaw the pipe in freezing weather, check the pressure, reset once.
E118 (low water pressure): "Water pressure LOW (<0.5 bar)".
Baxi's quick guide files it under "error codes that you can put right yourself". The one safe thing: top up through the filling loop to between 1 and 1.5 bar and reset. If you are doing that more than once or twice a year there is a leak, see boiler losing pressure.
E125 (circulation fault): "Water circulation fault", so water is not moving through the boiler as it should.
Behind it are low pressure, air in the system or a pump problem. The one safe thing: check the gauge and top up if it is low, bleed any radiator that is cold at the top, and reset once. If E125 comes back, the pump is the likely part.
E110 (overheat): "(i) Boiler max.
temperature exceeded for gradient (probable pump jammed or air in the circuit). (ii) Safety thermostat sensor tripped." The water heated faster than it should because it was not circulating. The one safe thing: check the pressure and reset once. A jammed pump or a safety thermostat is engineer work, and a boiler that overheats twice should be left off.
Newer Combi 2 and System 2 boilers use a different format: A.02.06 and H.02.07 are low pressure in the heating circuit, which Baxi's digital gauge guide says means top up; E.04.10 is "Burner failed to ignite after 4 attempts", the equivalent of E133; E.04.08 "Maximum safe temperature value reached" is the equivalent of E110.
E160 is a fan fault and E128 a lockout after "frequent loss of flame": reset once, and if the code returns that is a visit.
What can I safely check myself?
Everything here is done from the control panel, the gauge, the filling loop and the outside wall.
- Note the code, the gauge reading and the model on the front of the boiler.
- Reset once. On most Baxi boilers press the reset button until the red lockout light goes out; on older models the temperature knob or a selector switch has a reset position. Baxi's own rule: "If lockout occurs frequently a fault is indicated and you should contact your installer or service engineer."
- Pressure, for E118, E125, E110 and A.02.06. Cold, the gauge should sit between 1 and 1.5 bar. Open the filling loop, or the green Easyfill link on newer models, slowly, stop at about 1.2 bar and close it fully. Do not keep topping up if it falls straight back.
- Gas, for E133 and E.04.10. Light a hob or check another gas appliance, top up a prepayment gas meter, and check the gas cock at the meter is open.
- Condensate pipe, for E133, E119 or E28 in cold weather. Baxi's steps: switch the boiler off at the control panel and at the wall, find the frozen section, usually the most exposed part outside, warm it with a hot water bottle, a heat pack or warm water, never boiling, then switch the power back on and restart. From the ground only, and expect spilt water to freeze on the path. The full method is in frozen condensate pipe.
- Controls and power. If the display is dark rather than showing a code, check the fused spur, the timer and the thermostat, as in boiler not firing up after summer. Heating on but taps cold is usually a diverter valve, see no hot water but heating works.
Do not open the casing, and do not touch the pump, the fan or any wiring.
When do I stop and call an engineer?
- If you smell gas, leave the property, do not switch anything on or off, and call the National Gas emergency line on 0800 111 999 from outside.
- If water is dripping near the fused spur, sockets or the consumer unit, switch off at the main switch only if it is dry and safe to reach.
- Stop if the same code returns after one reset, if E110 or E.04.08 appears twice, if E160 appears at all, if E118 comes back within days of a top-up, or if E133 shows with the gas on and the condensate pipe clear.
- Gas work must be done by a Gas Safe registered engineer. Check the seven-digit number on the engineer's ID card at gassaferegister.co.uk, or text Gas and the number to 85080.
What does it cost in London?
A weekday call-out with diagnosis in London is £60 to £125, often waived if the repair goes ahead, and labour is £80 to £140 an hour. A pressure fault behind a repeating E118, meaning the expansion vessel or a valve, is £120 to £280 with the part. A pump behind E125 or E110 is £180 to £420, a fan behind E160 is £200 to £420 and a circuit board £290 to £650; most repairs, including the ignition parts behind E133, land between £150 and £400. Out of hours the first hour is £140 to £260.