Common problems guide

The most common Baxi Ecoblue Advance Combi problems

The faults most likely to send a Baxi Ecoblue Advance Combi into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

This model is discontinued. Parts can be harder to source and expensive. If repair costs are mounting, a new A-rated boiler may be the smarter choice.
24 documented codes
6 most common
3 DIY-safe checks
3 engineer needed

The 6 most common faults

01
E118 High DIY-safe

Your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.

What to try first

Locate the external filling loop, which is usually a flexible silver hose connecting two pipes underneath the boiler.Open the small tap or valve on the filling loop to allow cold mains water to enter the system until the pressure gauge reads between 1 and 1.5 bar.Close the tap firmly to stop the flow and check that the boiler restarts automatically.

Est. cost
£0-£80
Parts
Filling loop, Pressure relief valve, Expansion vessel
Full guide for E118
02
117 High DIY-safe

Your boiler has detected that the water pressure inside your heating system is too high, causing it to shut down for safety.

What to try first

Locate a radiator in your home, preferably one upstairs.Use a radiator bleed key to slowly open the bleed valve until a small amount of water drips out.Collect the excess water with a cloth and close the valve tightly once the pressure gauge on the boiler front panel drops back into the green zone (typically 1.0 to 1.5 bar).

Est. cost
£80-150
Parts
Pressure relief valve, Filling loop, Expansion vessel
Full guide for 117
03
118 High DIY-safe

Your boiler has stopped working because the water pressure inside the heating system has dropped too low.

What to try first

Locate the external filling loop, which is usually a flexible metal or silver braided hose underneath the boiler.Open the valves at both ends of the filling loop to let mains water into the system.Watch the pressure gauge on the front of the boiler until the needle reaches the green zone (typically between 1 and 1.5 bar).Close both valves tightly and ensure the filling loop is disconnected if it is a temporary type.

Est. cost
£80-150
Parts
Pressure Relief Valve, Pressure Sensor, Expansion Vessel
Full guide for 118
04
133 High Engineer

Your boiler has stopped working because it failed to light the flame needed to produce heat.

Est. cost
£150-300
Parts
Ignition electrode, Gas valve, PCB
Full guide for 133
05
20 High Engineer

Your boiler's temperature sensor for the heating system is not sending a proper signal, causing the boiler to stop working to protect itself.

Est. cost
£120-220
Parts
Central Heating NTC sensor, Wiring harness
Full guide for 20
06
28 High Engineer

Your boiler has detected a problem with the sensor that monitors the temperature of the exhaust gases exiting your home, preventing it from firing safely.

Est. cost
£150-250
Parts
Flue NTC Sensor, Wiring Harness
Full guide for 28
Parts most often replaced

on the Baxi Ecoblue Advance Combi

Filling loopPressure relief valveExpansion vesselPressure Relief ValvePressure SensorExpansion Vessel

Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.

Call a Gas Safe engineer if…

  • You can smell gas or see signs of a leak
  • The Baxi shows an Emergency or High severity code
  • The boiler keeps locking out after repeated resets
  • You've tried the DIY checks and the fault hasn't cleared
  • There's visible water leaking from the boiler
  • The flame is yellow or orange instead of blue
See the full 24-code list for the Baxi Ecoblue Advance Combi

Related guides

Boiler losing pressure → No hot water → When to replace → Symptom checker →