90 Medium

Ideal 90 Fault Code

The Ideal 90 fault code means: 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.. It appears on 3 Ideal models in our database.

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.

Technical description: NO CH OPERATION BUT DHW WORKS OK
Typical repair cost £150-300 (including labour)

Engineer required

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

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →
Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like 90: no call-out fees, no surprise bills.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

Ideal models that show the 90 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Ideal 90 fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026