Ideal Classic NF30–NF80 Fault codes & diagnostics

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

Regular Natural GasLPG 8.8-23.4 kW 1994-2003 Discontinued

Replaced by: Classic SE

Choose your boiler type

The Classic NF30–NF80 range comes in 6 types

Pick the one you have. The fault codes, GC numbers and manual differ by type.

Classic NF 30 3 codes · 1 GC number Classic NF 40 3 codes · 1 GC number Classic NF 50 3 codes · 1 GC number Classic NF 60 3 codes · 1 GC number Classic NF 70 3 codes · 1 GC number Classic NF 80 3 codes · 1 GC number
Each model has its own manual A family spans several manuals, one per model or generation. Pick your model above and its page has the manual its fault codes were read from.

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 Ideal Classic NF30–NF80 faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 3 documented codes

Tap any card for details

Neon I1

Your boiler is failing to start because it detects that the internal fan system is not operating correctly, likely due to a sensor incorrectly reporting air pressure levels before the system has even begun to run.

High Engineer only £150-250 Shared across the Ideal Classic NF range

Parts commonly replaced

  • Air pressure switch
  • Fan assembly
  • Venturi

Related codes

Full explanation for Neon I1
Neon I3

Your boiler is receiving power and is currently in its normal standby state, meaning it is ready to fire up whenever you turn on your heating or hot water.

Low DIY-safe Shared across the Ideal Classic NF range

What to check first

  1. No action is required as this is a normal operating status light
  2. Check your thermostat settings if you were expecting the heating to be on
Full explanation for Neon I3