Common problems guide

The most common Atag iC Economiser Plus problems

The faults most likely to send a Atag iC Economiser Plus into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

18 documented codes
6 most common
6 DIY-safe checks
0 engineer needed

The 6 most common faults

01
78 High DIY-safe

Your boiler has detected that the water pressure is either too low for the system to run or there is a problem with the sensor that measures it.

What to try first

Check the pressure gauge on the front of the boiler or the digital display.If the pressure is below 1.0 bar, use the filling loop valves to top up the system to 1.5 bar.Ensure the valves are fully closed after topping up and restart the boiler.

Est. cost
£80-220
Parts
Water pressure sensor, Filling loop, Expansion vessel
Full guide for 78
02
108 High DIY-safe

Your boiler has stopped working because the water pressure is too low and needs to be topped up.

What to try first

Locate the blue-handled filling link underneath the boiler.Slowly turn the lever(s) to allow water into the system while watching the pressure gauge.Close the lever(s) tightly once the pressure reaches between 1.2 and 1.5 bar.

Est. cost
£0-120
Parts
Filling loop, Expansion vessel, Auto air vent
Full guide for 108
03
110 High DIY-safe

Your boiler has switched itself off because it detected that the internal water temperature has become dangerously hot or a sensor has failed.

What to try first

Ensure all radiator valves are fully open to allow water to flow.Check that your boiler pressure is between 1 and 1.5 bar on the pressure gauge.Turn the boiler off and back on again once it has had 30 minutes to cool down.

Est. cost
£120-280
Parts
Flow/Return NTC Thermistor, Overheat Thermostat, Circulation Pump
Full guide for 110
04
111 High DIY-safe

Your boiler has switched itself off because it has become too hot internally, likely due to a lack of water flow or a blockage.

What to try first

Check that your central heating pressure is between 1.0 and 1.5 bar on the pressure gauge.Ensure all radiator valves and internal stop taps are fully open to allow water to flow.Try resetting the boiler by pressing the 'Reset' button on the control panel.

Est. cost
£120-450
Parts
Circulation Pump, Main Heat Exchanger, Overheat Thermostat
Full guide for 111
05
118 High DIY-safe

Your boiler has lost water pressure and has shut itself down to prevent damage to the internal components.

What to try first

Locate the filling loop (usually a silver braided hose with two black handles underneath the boiler).Slowly open both handles until you hear water entering the system.Watch the pressure gauge and close both handles once the needle reaches 1.5 bar.

Est. cost
£0-160
Parts
External filling loop, Expansion vessel, Pressure sensor
Full guide for 118
06
119 High DIY-safe

Your boiler has lost its internal electrical connection signal, which is usually caused by low water pressure or a loose wiring link inside the unit.

What to try first

Check the pressure gauge on the front of the boiler or via the display.If the pressure is below 1.0 bar, use the filling loop to top it up to 1.5 bar.Press the 'Reset' button (the one with the circular arrow) to clear the fault.

Est. cost
£80-160
Parts
Water pressure switch, Wiring harness connector, External controls link
Full guide for 119

on the Atag iC Economiser Plus

Water pressure sensorFilling loopExpansion vesselAuto air ventFlow/Return NTC ThermistorOverheat Thermostat

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

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See the full 18-code list for the Atag iC Economiser Plus