The deciding factor is evidence of sludge or restricted circulation, not simply the age of the heating system.
In Newry, this is usually a circulation and water-quality question. A power flush can remove iron-oxide sludge and debris from a wet central-heating system, but the symptoms need diagnosing first because trapped air, faulty valves, pump problems and poor balancing can produce similar complaints.
For the question “How much disruption does a power flush cause in a Newry home”, an engineer should compare radiator temperature patterns, system water condition, pump performance and circulation around the full circuit. Cold bottoms and dark system water point more toward sludge; cold tops are more commonly trapped air. A flush will not repair a failed valve, undersized pipework or a mechanical boiler fault, so it should be recommended for evidence of contamination rather than automatically.
After a successful clean, the system should be rinsed, protected with inhibitor and balanced correctly. Where appropriate, a magnetic filter can help capture circulating debris. BMK can assess the heating system in Newry first and only recommend power flushing where the symptoms and water condition justify it.