Baxi Boiler Fault Codes — Complete Guide for London Homeowners
Baxi boiler showing an error code? This guide covers every common Baxi fault code — what it means, what causes it, and whether you can fix it yourself or need a Gas Safe engineer.
Baxi Boiler Fault Code Quick Reference
Baxi boilers display fault codes on the control panel when they detect a problem. The format varies by model — older Baxi models use E followed by two digits (E1, E2), while newer models use a three-digit code (E119, E168, E160). Here are the most common codes homeowners encounter in London.
E119 — Low Water Pressure
E119 is the most common Baxi fault code in London properties. It indicates that the boiler water pressure has dropped below the minimum threshold (usually 0.8 bar). The boiler shuts down as a safety measure.
What causes it: Gradual pressure loss from a small leak in the system, a faulty pressure relief valve weeping, or normal system settling in newer installations. In London's hard water areas, scale buildup in the expansion vessel can cause false low-pressure readings.
What to do: Check the pressure gauge — if it reads below 1 bar, you can repressurise the boiler using the filling loop underneath. Turn both filling valves until the gauge reaches 1.5 bar, then close both valves. If the pressure drops repeatedly within days or weeks, there is a leak in the system that a Gas Safe engineer needs to find and repair.
E168 — Gas Supply or Ignition Fault
E168 appears when the boiler cannot ignite or loses flame during operation. This is the second most common Baxi fault code we encounter on London callouts.
What causes it: Gas supply interruption (check other gas appliances are working), a faulty gas valve, a dirty or failed ignition electrode, or low gas pressure at the meter. In older London properties with undersized gas supply pipes, high demand periods (winter mornings) can cause brief pressure drops that trigger E168.
What to do: First check your gas meter and other appliances. Try resetting the boiler once by holding the reset button. If the fault returns, call a Gas Safe engineer — do not attempt to work on gas components yourself.
E160 — Fan or Flue Fault
E160 indicates the boiler's fan is not running at the correct speed, or the flue is blocked or restricted.
What causes it: A failing fan motor, a blocked flue outlet (bird nest, debris, or in basement flats, the flue condensate drain freezing in winter), or a faulty air pressure switch.
What to do: Check the flue terminal outside the property is clear of blockages. Do not attempt to clear a flue internally — this requires a Gas Safe engineer. Frozen condensate in winter can be thawed by pouring warm (not boiling) water over the external condensate pipe.
E1 — Overheat/Thermostat Fault (Older Models)
Older Baxi models showing E1 have detected an overheating condition. The boiler's high-limit thermostat has tripped as a safety measure.
What causes it: Poor water circulation (seized pump, blocked heat exchanger, closed radiator valves), scale buildup on the heat exchanger in hard water areas, or a faulty thermostat.
What to do: Allow the boiler to cool for 20-30 minutes, then attempt a reset. If it repeatedly overheats, a Gas Safe engineer needs to diagnose the root cause — ignoring repeated overheating events can cause heat exchanger failure.
E2 — Sensor or Lockout (Older Models)
E2 on older Baxi models typically indicates a lockout condition caused by a failed sensor reading. The specific cause requires diagnostic equipment to identify precisely.
When to Call a Gas Safe Engineer
You should call a Gas Safe registered engineer immediately for any Baxi fault code that:
- Returns after resetting more than twice
- Involves a smell of gas anywhere near the boiler
- Is accompanied by any noise — banging, kettling, or hissing
- Causes complete loss of heating and hot water in cold weather
- Shows E160 or any fan/flue related code
Never attempt to open the boiler casing or work on gas components. All internal boiler work must be carried out by a Gas Safe registered engineer.
Frequently asked questions
What does E119 mean on a Baxi boiler?
E119 means the boiler water pressure is too low (typically below 0.8 bar). Check the pressure gauge and repressurise using the filling loop if it reads below 1 bar. If pressure drops repeatedly, you have a leak that needs a Gas Safe engineer.
How do I reset my Baxi boiler?
Press and hold the reset button (usually marked with a flame or reset symbol) for 3-5 seconds until the boiler attempts to fire. If the fault code returns, do not continue resetting — call a Gas Safe engineer to diagnose the underlying fault.
Why does my Baxi boiler keep losing pressure?
Repeated pressure loss indicates a leak in the heating system — either in a radiator valve, a joint in the pipework, or the expansion vessel. A Gas Safe engineer can carry out a pressure test to locate the leak.
Is E168 on a Baxi boiler dangerous?
E168 (ignition fault) is not immediately dangerous — the boiler has shut down safely. However, if you can smell gas, leave the property immediately, do not use any electrical switches, and call the National Gas Emergency line (0800 111 999).