BoilerFaultCodesThe 6 most common faults
01
HIGH High DIY-safe
Your boiler has detected too much water pressure in the system, which can put unnecessary strain on your pipes and internal components.
What to try first
Locate a radiator in your home, preferably one upstairs.Place a small container and cloth underneath the radiator bleed valve.Use a radiator key to slowly open the valve until water drips out, then close it once the pressure gauge on the boiler drops to between 1.0 and 1.5 bar.
02
STOP High DIY-safe
Your boiler is telling you that the internal water pressure is too low, so you need to open your filling loop to top it up to the correct level.
What to try first
Locate the filling loop, which is usually a silver flexible hose with one or two valves located underneath your boiler.Gradually open the valve(s) to allow water into the system while watching the pressure gauge on the front display.Once the needle reaches 1.5 bar, firmly close the valve(s) and ensure no water is dripping from the connection.
03
Block 60 High Engineer
Your boiler's internal computer settings for its power output have been lost or changed, which is preventing it from firing up correctly.
Full guide for Block 6004
Block 80 High Engineer
Your boiler has automatically shut down because the internal exhaust gases have become dangerously hot, and it will remain off until it cools down to a safe level.
Full guide for Block 8005
Block 81 High Engineer
Your boiler has detected that a critical safety sensor responsible for monitoring exhaust gases has become disconnected, so it has safely shut itself down to prevent operation.
Full guide for Block 8106
Block 82 High Engineer
Your boiler has stopped working because a sensor that monitors its exhaust fumes is reporting a fault, so the system has shut down as a safety precaution.
Full guide for Block 82on the Atag E22c
Pressure relief valvePressure gaugeFilling loop assemblyPressure sensorMain PCBFlue gas temperature sensor
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 Atag 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