Baxi E119 fault codewhat it means and how to fix it
System pressure has fallen below the level the boiler will operate at. Refilling to 1.2 bar and resetting usually clears it in a few minutes.
Take care
How quickly does the pressure fall after you fill it?
The right answer depends on what you can see. Pick the one that matches.
Choose the option on the left that matches what your appliance is doing, and the answer for that case appears here.
It holds for months
Normal. Top up and carry on; once or twice a year is expected.
It falls again within a few weeks
A slow leak or a tired expansion vessel. Worth diagnosing before the constant refilling corrodes the system.
Ask for a pressure test and for the expansion vessel charge to be checked.
It falls within hours
A real leak, and possibly one causing damage you have not found.
Stop refilling, turn the boiler off, and get someone out.
What E119 means
E119 is Baxi reporting low water pressure in the sealed heating circuit. Below roughly 0.5 bar the boiler stops the burner, because heating a heat exchanger that does not have enough water flowing through it wrecks it quickly. The lockout is the appliance protecting itself and it is doing the right thing. What matters is the reason the pressure fell, because a sealed system does not consume water. Somewhere it is escaping: a weeping valve, a joint under a floor, an expansion vessel that has lost its charge, or a pressure relief valve holding slightly open on a bit of debris.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| Corroded radiator letting go | A pinhole through a rusted panel, often on a towel rail or a radiator in a bathroom. Frequently marked by a rust-coloured crust rather than an obvious puddle. | Common |
| Valve gland weeping | The packing behind a radiator valve handle dries and seeps. Usually cured by a quarter turn on the gland nut rather than a new valve. | Common |
| Vessel charge gone | Baxi appliances often carry the vessel behind the heat exchanger, which makes it awkward to reach and correspondingly likely to have been skipped at every service so far. | Occasional |
| Automatic air vent leaking | The small brass vent on top of the pump or manifold can pass water instead of air once the seal hardens. It drips inside the case rather than outside, so nobody sees it. | Occasional |
What to try yourself
Take the reading cold. On a Duo-tec the pressure appears on the LCD behind the front flap rather than on a separate dial.
Look underneath for the filling loop. Baxi installations vary — some have the braided hose, others a pair of chrome taps on the pipework, and a few use an internal keyed link.
Open both ends slowly. You should hear water moving. Bring it to 1.2 bar and no further.
Overfilling is not harmless on an older system. Pushing past 2.5 bar cold can start a weep at a joint that had been perfectly sound.Close both ends firmly and check they are shut by feeling whether the hose has gone quiet and cool.
Record the date. Two top-ups a year is tolerable; four is a leak that will cost less to find now than to live with.
Get a Gas Safe registered engineer to look at your Baxi E119
Gas Safe Register engineers only. No obligation.
What it costs to fix
Typical repair cost
£0–£450
Time on site
10 minutes
Free to top up. Leak trace £90–£160. Expansion vessel £150–£280.
Typical UK prices including parts and labour, updated August 2026. Your quote may differ.
Parts you may need
We may earn a commission if you buy a part through one of these links. It does not change what you pay, and it does not affect which parts we list.
Expansion vessel (8 litre, sealed system)
EV-8L£35–£85Plumbing merchant
Price checked 5 August 2026
Pressure relief valve, 3 bar
PRV-3B£18–£42Plumbing merchant
Price checked 5 August 2026
What other owners found
Nobody has shared what worked for them on this code yet. If you have had it, you would be the first — and it genuinely helps the next person.
Related Baxi fault codes
- F.22Get it checkedThe boiler has shut down because there is not enough water in the system. Pressure has dropped below roughly 0.5 bar and it will not fire until you top it up.Related: water pressure
- F.75Get it checkedThe boiler cannot detect a rise in pressure when the pump starts, so it has locked out. Usually a failed pressure sensor or a pump that is not moving water.Related: water pressure
- F1Get it checkedSystem pressure has dropped below the minimum the boiler will run at. Topping it back up to 1.2 bar usually clears it straight away.Related: water pressure
- CE 207Get it checkedSystem water pressure has dropped too low for the boiler to run safely. Topping the system back up to 1.2 bar usually clears it in five minutes.Related: water pressure
- E10Usually simple to fixSystem water pressure has fallen too low for the appliance to fire. Top the system back up to 1.2 bar and it will restart.Related: water pressure
- 108Usually simple to fixThe heating circuit does not contain enough water to run safely. Refill through the filling loop to about 1.2 bar and the code clears.Related: water pressure
Related guides
Common questions about Baxi E119
What pressure should a Baxi boiler be at?
1.0 to 1.5 bar cold, with 1.2 bar the usual target. Higher when hot is normal and expected. Always set it with the system cold, not after the heating has been running.
Is E119 the same as E118?
They are closely related — both concern system pressure — but they are separate conditions and the boiler distinguishes between them. Quote the exact number you can see rather than the one you half remember, because it changes what the engineer checks first.
Can I fill it while the boiler is hot?
Better not to. Water expands as it heats, so filling to 1.2 bar hot means it will sit too low once cold. Let it cool, then fill.
Sources and how we verified this
We establish the facts from the sources below and then write the explanation ourselves. We do not copy manufacturer wording and we do not host their manuals.
- Manufacturer technical and service documentation
- Manufacturer support portal
- Interviews with working engineers
Checked by Technical reviewer (Gas Safe registration to be displayed on appointment) on 5 August 2026.