Why annual is the right interval
- Manufacturer warranties (Worcester, Ideal) require yearly RGII servicing
- Catches small faults — sticking pumps, blocked condensate, weak valves — before they fail
- Restores efficiency: a serviced boiler runs up to 15% leaner
- Carbon-monoxide safety check on the gas side
- Required under Residential Tenancies Board (RTB) rules for landlords
When to service sooner
Service immediately — don't wait for the anniversary — if you notice yellow flames instead of blue, a sooty boiler casing, persistent pressure loss, kettling or rumbling noises, or a CO alarm activation. Each is a sign of unsafe combustion or imminent failure.