How to tell if your system needs a power flush
Unless your system has been flushed through with clean water and an inhibitor added when installed, it starts to deteriorate. The steel and copper components will start to react with each other. The steel becomes sacrificial to the copper and is slowly dissolved through electrolytic action causing magnetite (black sludge) in the system. This process dissolves the walls of the radiators and will eventually cause leaks. As the build up of sludge increases it can block waterways and seriously impair the efficiency of your heating system, leading to higher fuel bills and failure of the pump, radiator valves and boiler. Corrosion can also be a problem if air id being drawn into the system introducing oxygen which will react with the steel causing red rust.
If you have radiators that are hot at the top and have cold spots at the bottom, this is normally due to a build up of sludge or rust flakes blocking the waterways within the radiator. If your radiators have cold spots at the top of the radiator this is probably due to air (hydrogen gas) in the system collecting in the radiators, this is a by-product of the electrolytic action. If your system is regularly topped up with fresh water and you live in a hard water area, a build up of limescale in the system is possibly causing added problems.
The following are all symptoms
- Black water in the system
- Radiators requiring frequent bleeding
- Radiators partially or completely cold.
- Pinhole leaks from radiators
- Blocked, inoperative or leaking radiator valves.
- System very slow to warm up.
- Noisy boiler (kettling or banging).
- Noisy central heating pump.
- Central heating pump failure.
If you recognise any of these symptoms, your heating system would certainly benefit from power flushing.
The power flush process
Power flushing is the most efficient and effective method of cleansing a central heating system. The principle is to circulate a cleansing chemical and water mixture under controlled conditions to remove debris from the system. The chemical water has a high flow rate but not much pressure, so your existing pipework remains quite safe. By connecting the power flushing pump to the heating circuit in place of the central heating system pump, boiler or radiator, the circuit can be thoroughly cleansed of limescale, sludge and debris.
What happens during a power flush?
The power flushing pump is simply connected into the heating system, either across the standard circulator pump couplings, across the tails of one radiator, or wherever most practicable.
Power flushing is a highly effective cleansing operation which works by pumping water at a much higher velocity than usual through the heating system, to loosen and mobilise harmful deposits, and to suspend them in the rapidly moving water. The process is made more effective by specialist cleansing chemicals, and an instantaneous flow reversal device, which creates turbulence in the radiators to optimise ‘pick up’ of the debris.
Once loosened, the unwanted debris is purged from the system with clean water. At the end of the flushing process, the system contains fresh clean water, and reinstatement of the system to normal operation takes only a few minutes.
During the process, radiators are individually flushed, without removing or disconnecting them from the system, by directing the full output of the pump through each radiator separately. A vibrating tool is used along the bottom of each radiator to aid cleansing.
Power flushing is not a high pressure operation, and it is suitable for most domestic wet central heating systems. It is carried out with minimal disturbance and disruption to the normal operation of the system, often without disconnecting the boiler or any radiators.
Once your whole system has been power flushed thoroughly, we will refill it with clean water, and an inhibitor will be added to your central heating system. This will be clearly labelled as containing this chemical substance. Power, or system flushing can take up to a day to complete, but the timing depends on the number of radiators and the type of system you have.
Additional information
The objective of power flushing is to restore systems with circulation and boiler noise problems (caused by sludge and corrosion deposits) to optimum operation. Power flushing removes these deposits and the problems they cause.
The success of a power flush will depend on the level of the heating system deterioration which has occurred beforehand. The process will cure most circulation problems, but cannot undo the corrosion and gradual decay that has led to the need to power flush the system.
While it is rare for a heating system to experience leaks after the power flushing process, it is not possible to inspect a system internally beforehand, and the need to use a flushing and dispersing chemical for effective cleansing means that occasionally we may find a leak.
The advanced stage of corrosion required for such a situation means that the leak would occur, imminently even without a power flush. We believe that it is better that it occurs whilst we are present to remedy the problem, rather than for it to arise over a weekend or while the house is unoccupied.
Systems that have been neglected over a period of time, or have not been treated with an effective corrosion inhibitor, may have severely compacted corrosion debris in the pipework, radiators or boiler, and it is possible that even after the power flush, some radiators may still not be fully effective or boilers on the margin of failure may cease working due to sludge and debris later breaking loose and collecting in the heat exchanger. As additional protection a Magnaclean Filter can be installed into the boiler return pipe to ensure, any sludge particles circulating are trapped before they enter the boiler.
Condensing boilers
If you are upgrading your system with a new high efficiency condensing boiler then power flushing is essential if you want to realise the published energy efficiency levels of 90% - 94%. Your new boiler cannot be expected to fulfil its potential if your heating system is full of sludge and scale.
Modern boilers have much smaller waterways and are therefore far more prone to clogging than their predecessors.
Most boiler manufacturers insist that the system is thoroughly flushed as a requirement of their warranty.
