Common problems guide

The most common Baxi Ecoblue 15 System ErP problems

The faults most likely to send a Baxi Ecoblue 15 System ErP into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

28 documented codes
6 most common
5 DIY-safe checks
1 engineer needed

The 6 most common faults

01
E118 High DIY-safe

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

What to try first

Locate the filling loop, which is usually a flexible silver hose with one or two valves underneath the boiler.Open the valve(s) slowly to allow cold mains water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close the valve(s) tightly and check that the fault code has cleared.

Est. cost
£0-90
Parts
Filling loop, Pressure relief valve, Pressure sensor
Full guide for E118
02
133 High DIY-safe

Your boiler has tried to start up several times, but the internal flame is failing to ignite or stay lit.

What to try first

Check your gas supply by testing another gas appliance, such as a cooker, to ensure gas is reaching your home.Check your prepaid gas meter (if you have one) to ensure you have credit.Locate the reset button on your Baxi boiler, press and hold it for at least 5 seconds, and let the boiler attempt to restart.

Est. cost
£150-300
Parts
Ignition lead, Electrodes, Gas valve
Full guide for 133
03
117 High DIY-safe

Your boiler has detected that the water pressure inside your heating system is currently too high for safe operation.

What to try first

Locate a radiator in your home, preferably one upstairs.Using a radiator bleed key, open the bleed valve slightly until a small amount of water comes out to release pressure.Check your boiler's pressure gauge and ensure the needle has dropped back into the green zone (usually 1.0 to 1.5 bar).

Est. cost
£80-150
Parts
Pressure relief valve, Filling loop, Pressure sensor
Full guide for 117
04
118 High DIY-safe

Your boiler has stopped working because the amount of water circulating inside your heating system has dropped below the required level.

What to try first

Locate the filling loop (a silver flexible hose) underneath the boiler.Open the valves at both ends of the hose to allow water into the system.Watch the pressure gauge on the front of the boiler until the needle reaches 1.5 bar, then firmly close both valves.

Parts
Pressure relief valve, Pressure sensor, Expansion vessel
Full guide for 118
05
I High DIY-safe

Your boiler has stopped because the water pressure inside the heating system is either too low or too high.

What to try first

Locate the filling loop valves connected to your boiler.If the pressure is below 0.5 bar, slowly open the valves to let water in until the gauge reads between 1.0 and 1.5 bar, then close them tightly.If the pressure is above 2.7 bar, bleed a radiator to let out excess water until the pressure drops back into the normal range.

Parts
Pressure relief valve, Expansion vessel, Filling loop
Full guide for I
06
20 High Engineer

Your boiler's temperature sensor is providing faulty readings, so the system has shut down to prevent overheating or operating incorrectly.

Est. cost
£120-200
Parts
Central heating NTC sensor, Wiring harness
Full guide for 20

on the Baxi Ecoblue 15 System ErP

Filling loopPressure relief valvePressure sensorIgnition leadElectrodesGas valve

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

Avoid the next call-out bill

Monthly cover means no unexpected bills when your boiler breaks down.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

See the full 28-code list for the Baxi Ecoblue 15 System ErP