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Key takeaways
- E119 is a pressure fault, not a gas or ignition fault. The gauge will usually read 0 or below 1 bar.
- Baxi says you can top up yourself using the boiler’s filling link. Aim for the range in your user manual, typically 1 to 1.5 bar when cold.
- Recently bled radiators are a common, harmless cause. Repeated E119 means a leak or a component fault.
- E119 is different from E133, which is Baxi’s ignition or gas supply fault.
- Never open the casing. If you are unsure about topping up, call an engineer or Baxi.
The Baxi E119 error means your boiler has detected that the water pressure in the heating system is too low, so it has stopped working to protect itself. Baxi’s own help page describes E119 and E118 as the boiler detecting that “the pressure is too low”. In most cases you can top up the pressure yourself using the filling link under the boiler and reset it. If E119 keeps coming back, water is escaping from the system and a heating engineer needs to find out where.
What does E119 mean on a Baxi boiler?
Baxi combi and system boilers run on a sealed heating circuit filled with water under pressure. A sensor checks that pressure before the boiler fires. If it falls too low, the boiler shows E119 and locks out. You lose heating, and on a combi you usually lose hot water too.
Baxi’s E119 and E118 self-help page groups both codes under low pressure and lists two common causes: radiators that have recently been bled, and a leak somewhere in the heating system. On some Baxi models E118 and E119 appear at different pressure levels or stages, so check your user manual for exactly what each means on your boiler. The fix starts the same way.
Baxi E119 vs E133: which fault do you have?
Baxi owners often see two codes in winter, and they mean very different things.
| E119 (and E118) | E133 | |
|---|---|---|
| What it means | Heating system water pressure too low | Boiler failed to light or detect a flame |
| Pressure gauge | Usually 0 or below 1 bar | Usually normal |
| Common causes | Bled radiators, leak, relief valve, expansion vessel | Gas supply off or meter credit, frozen condensate, ignition fault |
| What you can do | Top up with the filling link, then reset | Check gas supply and condensate, then reset once |
| When to call an engineer | If pressure keeps dropping or E119 shows at normal pressure | If it keeps locking out after basic checks |
If your gauge reads normal and the code is E133, see our guide to the Baxi E133 error code instead.
How to fix Baxi E119: top up and reset
Baxi says you can top up the pressure yourself. The method depends on your model, so check the user guide or Baxi’s video for your boiler. The general process is:
- Turn the heating off and let the system cool. Topping up a hot system gives a false high reading.
- Find the filling link. Many newer Baxi boilers have a permanent filling link under the boiler, which Baxi calls Easy-Fill. Older models may have a braided filling loop with two valves, or a key that has to be fitted.
- Open the filling valves slowly. On many models these are levers that you turn to line up with the pipework. You will hear water flow in.
- Watch the gauge and close the valves when it reaches the figure in your manual. A council tenant guide for the Baxi Duo-tec, for example, says to close the levers when the gauge reaches 1.5 bar.
- Make sure the valves are fully closed. A valve left slightly open will keep letting water in, which can push the pressure too high.
- Reset the boiler. Reset methods vary by model. On the Duo-tec, the Ashfield District Council tenant guide says to turn the selector to reset and hold it fully left for five seconds. Newer models use a reset button; follow your user guide.
For pictures of the different filling loop types, see our step-by-step guide on how to repressurise a combi boiler. If you rent your home, tell your landlord or letting agent before touching the boiler, as they may prefer to send their own engineer.
Why does my Baxi keep showing E119?
One E119 after bleeding a few radiators is normal. Bleeding lets air out, the system loses a little volume, and the pressure falls. A single top-up sorts it. Baxi suggests that if you keep needing to top up, you ask your installer or Baxi to check the rest of the system.
Pressure that keeps falling means water is going somewhere. The usual places:
Pressure relief valve
This safety valve lets water out through a copper pipe that usually ends outside, if pressure gets too high. Over-filling, a failed expansion vessel or a worn valve seat can all make it drip. Check the end of the pipe for drips or staining. Our guide to a pressure relief valve dripping outside explains what that means.
Expansion vessel
The expansion vessel absorbs the increase in water volume as the system heats. If it loses its air charge, pressure shoots up when hot, the relief valve opens, and the pressure then drops too low when the system cools. A clue is a gauge that swings widely between cold and hot. Recharging or replacing the vessel is an engineer job.
Leaks on radiators, valves and pipework
Look round radiator valves, towel rails and visible pipe joints for drips, damp or crusty green or white deposits. Hidden leaks under floors are harder to spot. Our article on a boiler losing pressure with no visible leak works through the less obvious places.
Leaks inside the boiler
Seals around the pump, heat exchanger or valves can weep. If you see water under the boiler or rust marks on the casing, switch off and call an engineer. Do not take the cover off.
Cold weather pressure drops
Pressure naturally falls a little when the system is cold, and some homes see E119 on frosty mornings when the gauge was only just above the minimum. If that is the only time it happens, the system may simply need topping up to the right cold pressure. Our guide on boiler pressure dropping in cold weather covers this.
E119 with the gauge reading normal
If E119 appears while the gauge shows healthy pressure, the boiler and the gauge disagree. The likely causes are a faulty pressure sensor or switch, a wiring problem, or a gauge that is itself inaccurate. All of these are inside the boiler. Keep resetting and you are only clearing the symptom. Book a Gas Safe registered engineer to test the sensor and wiring.
If you smell gas at any point, open windows, do not use electrical switches, turn off the gas at the meter if you can, leave the property and call the National Gas Emergency Service on 0800 111 999.
Preventing E119 on a Baxi boiler
- Check the gauge once a month in winter, with the system cold, so you catch a slow drop early.
- Top up after bleeding radiators, every time.
- Do not over-fill. Too high a pressure makes the relief valve work and leads to the next drop.
- Keep up annual servicing. Engineers check the expansion vessel charge and look for leaks. Our Baxi boiler service guide lists what is covered.
Need help with a Baxi E119 fault?
Top up to the pressure in your manual, close the valves fully and reset. If E119 returns within days, or appears at normal pressure, there is a leak or a component to fix, and that is a job for an engineer.
Gasmaster’s Gas Safe registered engineers repair Baxi boilers across Stoke-on-Trent, Staffordshire, Cheshire and Derbyshire. Visit our boiler repair page or contact us to book an engineer.
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Frequently asked questions
What should the pressure be on a Baxi boiler?
Most Baxi user guides give a cold system pressure of around 1 to 1.5 bar. The exact figure for your model is in the user manual and sometimes marked on the gauge. It will rise when the heating is on, which is normal. Check it with the heating off and the radiators cool for an accurate reading.
Is it safe to top up a Baxi boiler myself?
Yes, Baxi says owners can top up the pressure using the filling link, and it provides videos for its boilers. Go slowly, stop at the recommended pressure and close the valves fully. If the valves are stiff, you are unsure which ones they are, or water appears anywhere it should not, stop and call an engineer.
Why does my Baxi lose pressure overnight?
Losing pressure overnight usually means a leak somewhere in the system or a relief valve letting water out. It can also be an expansion vessel fault, where pressure rises when hot, the relief valve vents, and then pressure crashes as the system cools. An engineer can test the vessel and trace the leak.
Will E119 damage my boiler?
No, E119 is the boiler protecting itself. It stops firing before low water can cause overheating. Problems come from ignoring the cause: a leak can damage floors, ceilings and electrics, and a relief valve that keeps opening can wear out. Fix the underlying fault rather than topping up week after week.
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Abdul runs Gasmaster Plumbing & Heating and has worked on boilers, heating and gas appliances across Stoke-on-Trent since 2005. He is Gas Safe registered (reg. 220932), and these articles come from his day to day work in homes and businesses across Staffordshire, Cheshire and Derbyshire.
