The main reason for the black sludgy water that is found in central heating systems is corrosion. This sludge gets all round the system and can result in cold spots in radiators, radiator valves blocking, motorised valves passing, pumps failing, boiler parts blocking and in the worst cases the pipework gets lined with it which reduces the bore of the pipework or blocks it completely.
Too often new boilers are fitted to old heating systems that have never been flushed out or treated with inhibitor and end up needing expensive parts or even the whole boiler replacing.
If you are experiencing any of the above symptoms you may need a flush.
Sometimes when working on your system TW Gas & Heating may identify a flush is required and will always to show you why.
Given that all systems are different in size / design and have various type of boiler attached TW Gas & Heating will assess the extent of the problem and give you a personal quote for a flush. Cleaner will be added to the system before the flush and inhibitor will be added after.
With older systems it may sometimes be advisable / cost effective to fit new radiator valves at the same time as a flush.
Magnetic system filters can also be supplied and fitted either as an individual system upgrade or as an extra with a power flush.