Common problems guide

The most common Atag iC Economiser 27 Plus problems

The faults most likely to send a Atag iC Economiser 27 Plus into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

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

The 6 most common faults

01
101 High DIY-safe

Your boiler has become too hot and has shut itself down as a safety precaution to prevent damage.

What to try first

Check that your radiator valves are open to allow water to flow.Ensure the system pressure is between 1.0 and 1.5 bar on the pressure gauge.Press the Reset button on the control panel to see if the fault clears.

Est. cost
£150-450
Parts
Circulation pump, Overheat thermostat, Heat exchanger cleaning/flushing
Full guide for 101
02
104 High DIY-safe

Your boiler has detected that water is not circulating correctly through the system, which prevents it from heating up safely.

What to try first

Check that the boiler pressure gauge is between 1.0 and 1.5 barEnsure all radiator valves and isolation valves under the boiler are fully openBleed all radiators to remove trapped air bubbles from the pipeworkReset the boiler using the reset button once pressure is confirmed

Est. cost
£120-£350
Parts
Circulation Pump, Water Pressure Sensor, Main Heat Exchanger (Flushing)
Full guide for 104
03
108 High DIY-safe

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

What to try first

Locate the filling loop or key underneath your boiler.Open the valves slowly to let mains water into the heating system.Watch the pressure gauge on the front of the boiler until the needle reaches between 1.0 and 1.5 bar, then close the valves tightly.

Parts
Filling loop, Pressure relief valve, Pressure sensor
Full guide for 108
04
1P4 High DIY-safe

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

What to try first

Locate the filling loop valves underneath your boiler.Open the valves gently to allow water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close the filling loop valves tightly and reset the boiler.

Parts
Filling loop, Pressure relief valve, Pressure sensor
Full guide for 1P4
05
140* High DIY-safe

Your boiler has stopped working because it cannot detect the water pump moving or the correct water pressure needed to operate safely.

What to try first

Check that your boiler pressure gauge is between 1 and 1.5 barIf pressure is low, top up the system using the filling loopRestart the boiler by pressing the Reset button

Est. cost
£180-350
Parts
Circulating Pump, Water Pressure Sensor
Full guide for 140*
06
501 High DIY-safe

Your boiler is failing to light the gas, which means it cannot provide the heating or hot water you need.

What to try first

Check that your gas supply is turned on and other gas appliances are working.If you have a prepay meter, ensure you have sufficient credit.Press the Reset button once to see if the boiler restarts.

Est. cost
£100-350
Parts
Ionisation probe, Ignition electrode, Gas valve
Full guide for 501

on the Atag iC Economiser 27 Plus

Circulation pumpOverheat thermostatHeat exchanger cleaning/flushingCirculation PumpWater Pressure SensorMain Heat Exchanger (Flushing)

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

Avoid the next call-out bill

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See the full 16-code list for the Atag iC Economiser 27 Plus