Overview
E119 on a Baxi EcoBlue means the boiler has detected low water pressure in the sealed central heating system. When pressure falls below the minimum threshold the boiler will often lock out or reduce operation to protect itself — this commonly causes loss of heating and hot water or prevents the boiler from firing. Low pressure itself is common and frequently straightforward to correct by adding water to the system. Pressure can drop for ordinary reasons (bleeding radiators, minor slow loss over time) or because of a fault (a leak in a pipe, radiator or valve, a dripping pressure relief valve, or a failing expansion vessel). The immediate severity is usually low — the boiler typically won’t pose an immediate safety risk — but the fault will stop normal heating/hot water and, if pressure keeps falling, it indicates a problem that needs attention. Topping the pressure up is a job many homeowners can do safely if they are confident and follow instructions. Any work involving gas components, internal boiler parts, a suspected leak, a leaking safety valve, or suspected expansion vessel failure should be left to a qualified Gas Safe registered heating engineer. Do not attempt gas or internal repairs yourself.
Possible Cause: System pressure too low
Troubleshooting Steps
Safety first
- Turn the boiler off at the programmer/room thermostat and switch off the electrical supply at the isolator. Allow the boiler to cool before touching pipework.
- Have a towel and a small container ready in case a few drops of water escape. Work in daylight or with a torch so you can see valves and the pressure gauge clearly.
- If you are unsure, uncomfortable or the system shows obvious leaks or dripping from safety pipework, call a Gas Safe engineer. Do not attempt gas or internal repairs yourself.
Initial visual checks you can do
1. Check the pressure gauge on the boiler. If it reads below about 1.0 bar (often in a red zone) the E119 low-pressure error is expected.
2. Look for visible leaks around pipework, radiators, valves and the floor beneath the boiler. Check the condensate/PRV discharge pipe (usually a small plastic pipe) for signs of recent water.
3. Note whether you have recently bled radiators or had work done on the heating system — bleeding can lower system pressure.
4. Listen for any unusual noises when the system is on or trying to fill. If the gauge does not move when you try to fill, there may be a closed mains stopcock or a blocked valve.
How to repressurise the system (general steps)
- Refer to your boiler manual for model-specific details and the correct target pressure. Aim for the green zone or about 1.0–1.5 bar on most Baxi combi boilers (some guidance says into the green area on the gauge).
- Locate the filling loop under the boiler. It is either a flexible hose with two small valves or a built-in ‘easy fill’ lever/valve (green lever on some Baxi models).
- For an Easy-Fill permanent filling link: push or operate the easy-fill lever slowly and hold while watching the pressure gauge. Release as soon as the gauge reaches the correct pressure and let the lever return to off.
- For a removable filling loop: ensure both isolating valves are closed, attach the filling loop if it’s not already attached, open one valve then slowly open the other valve until the pressure gauge rises to about 1–1.5 bar. Close both valves fully, remove the loop if non-permanent, and replace the end caps. Wipe away any drips.
- Don’t over-pressurise. If the needle goes well above the recommended range, slowly bleed a radiator to bring pressure down and then top up to the correct level.
After topping up
- Turn the boiler back on and check whether the E119 error clears. Some boilers clear automatically once pressure is correct; others may require you to reset following the manufacturer’s instructions.
- Run heating and hot water briefly, then re-check the pressure. If you had to bleed radiators, top up again afterwards because bleeding releases water/air and lowers pressure.
When the problem is not fixed or keeps returning (call a professional)
- If you cannot get the pressure to rise when using the filling loop (no water flow), if the gauge doesn’t move, or if you see leaks or dripping from the pressure relief pipe, stop and call a Gas Safe registered heating engineer.
- If the pressure falls again shortly after topping up or keeps dropping over days or weeks, this indicates a leak or a fault (e.g. pressure relief valve, automatic air vents, or expansion vessel). These require a qualified engineer to diagnose and repair.
- If you suspect the expansion vessel is faulty (pressure fluctuates excessively when system heats/cools) or the pressure relief valve is discharging, do not attempt to repair these yourself — call a Gas Safe engineer.
Additional notes and cautions
- Never attempt internal boiler or gas valve work unless you are a registered gas engineer. In the UK any repairs to gas appliances must be done by a Gas Safe registered engineer.
- Keep an eye on the system for a few weeks after topping up. Recurrent loss of pressure is the key sign that professional investigation is needed.
- If you are unsure at any point, err on the side of safety and book a qualified heating engineer to inspect the boiler.
Helpful Resources
Boiler Manual
Download the official PDF manual for the Baxi EcoBlue.