BoilerFaultCodesIdeal 53 Fault Code
The Ideal 53 fault code means: your boiler's small starter flame is lit, but the main burner is failing to ignite because it isn't receiving the gas flow it needs to heat your home.. It appears on 3 Ideal models in our database.
Technical description: PILOT LIT BUT NO MAINS GAS
What causes the Ideal 53 fault?
This fault occurs when the boiler successfully lights its small pilot flame but fails to transfer that flame to the main burner. The most common reason is a mechanical failure within the gas valve or a faulty electronic command from the control board, preventing the main flow of gas from being released. It essentially means the ignition process has started, but the 'full' heat cannot be triggered.
This issue is more frequent during the first cold snap of autumn, as gas valve internal components can seize up after being inactive throughout the summer months.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Search the official register for a qualified engineer in your area.
Gas Safe Register →Ideal models that show the 53 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal 53 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