Medium
90 on Ideal Atlantic Combi

Your boiler is still providing hot water for your taps, but it has stopped communicating with your heating system, so your radiators will not turn on.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

NO CH OPERATION BUT DHW WORKS OK

From this model's manual
Verified against the Ideal/Ideal Atlantic Combi installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

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All 59 fault codes on the Atlantic Combi

Seeing a different code? Every code this model can display, in one place.

4.34.44.54.64.74.84.94.104.114.12828384858689F[-]F1F2F2 or Fn or LnF3F4F5F6F7F8F8 or L8F8/L8F9F9 or L9F9/L9FAFan faultFlame lossFlow thermistor faultFnFUIgnition lockoutL 2L CL[-]L1L4L4 or F4L5L5 or F5L6L8L9LnLow mains voltageLow water pressureNo DisplayOutside sensor faultOverheat lockoutPCB FaultReturn thermistor faultWater Pressure

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