Atag iC Economiser 30 Fault codes & diagnostics

3 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

Combi Natural Gas 30 kW 2018-present

The fault code is already on your display

Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →

Just want the most common Atag iC Economiser 30 faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 3 documented codes

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50

Your boiler has detected a problem with the sensor that manages your hot water temperature, which may result in your taps running cold or having inconsistent heat.

Medium Engineer only £90-160

Parts commonly replaced

  • DHW NTC Temperature Sensor
  • Sensor wiring harness
Full explanation for 50
117

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

High DIY-safe £100-280

What to check first

  1. Check that the filling loop valves are fully closed
  2. Bleed water from a radiator using a bleed key to reduce the pressure
  3. Monitor the pressure gauge until it returns to between 1.0 and 1.5 bar
  4. Reset the boiler once the pressure is within the normal range

Parts commonly replaced

  • Filling loop valve
  • Expansion vessel
  • Pressure relief valve (PRV)
  • Water pressure sensor

Related codes

Full explanation for 117
118

Your boiler has detected that the water pressure is too low for it to operate safely, or it is struggling to move water through the system.

High DIY-safe £0-280

What to check first

  1. Check the pressure gauge on the front of the boiler; it should ideally be between 1.2 and 1.5 bar.
  2. Locate the filling loop (usually a silver braided hose with small black lever valves) underneath the boiler.
  3. Slowly open the valves to let water in until the gauge reaches 1.5 bar, then ensure they are closed tightly.
  4. Press the Reset button on the control panel to clear the fault.

Parts commonly replaced

  • Circulation pump
  • Water pressure sensor
  • Automatic air vent

Related codes

Full explanation for 118