BoilerFaultCodesIdeal 28 Fault Code
The Ideal 28 fault code means: your boiler is not receiving a steady supply of gas or has air trapped in the pipes, preventng the flame from lighting properly.. It appears on 3 Ideal models in our database.
Technical description: The burner is supplied with too little gas or air is present in the gas pipe; check the pre-pressure. If the control pipe is not blocked, the gas/air ∆P should be checked at minimum and maximum load.
What causes the Ideal 28 fault?
This fault occurs when the boiler's burner fails to receive the correct amount of gas required to create or maintain a stable flame. It is usually caused by air being trapped within the internal pipework after maintenance, or a failing gas valve that can no longer regulate the fuel flow correctly. Because the boiler cannot guarantee a safe and consistent burn, it will shut down to prevent damage or unsafe operation.
This issue can occasionally appear during the first cold snap of autumn when a boiler that has been idle all summer is suddenly forced to operate at maximum gas demand.
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 →Ideal models that show the 28 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal 28 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 27 April 2026