Magnetite sludge removal

[Sam654]

I have a significant buildup of magnetite in a central heating system with several miles of pipe at a site in GA. As you can expect, we have HX's plugging constantly. The system supplies both heating in the winter and domestic hot water year round. Pipe size ranges from 16" leaving the central energy plant to 1" in some buildings.

During summer months (~8 months in GA), flow is reduced significantly with the reduced heating system load. I suspect during this time, some sludge is settling out and is picked up when flows are increased in the heating season.

Is there some method of cleaning this huge system with minimal interruption? There has been little maintenance on the piping system outside of maintaining a pH >8 with an amine.

 

[BigInch]

Make the problem lines piggable, or install flushing taps?

 

[bimr]

Magnetite is a particular problem in London with the many central heating plants located there.

Powerflushing is arguably the most effective procedure (although it is important to check the boiler manufacturer's instructions to establish whether powerflushing is acceptable with the boiler in circuit). Powerflushing is a particularly effective method of cleansing existing systems, especially those containing a high level of black magnetite sludge.

http://wiki.diyfaq.org.uk/index.php?title=Central_heating_flushing

To minimize scaling in the future, consider the installation of water treatment equipment to remove the scale formers in the makeup water.

http://www.wwdmag.com/channel/casestudies/dissolved-gas-control

 

[btrueblood]

Stick some nickel-plated magnets in an inline tee-strainer, and service/clean them regularly.