MagnaClean CMX® filters improve heating system reliability and reduce costs for UK Social Housing Schemes


When a social housing provider based in the Midlands decided to address heating systems and system water quality in more than 30 accommodation blocks across the city, they contacted their main contractor who asked Dodd Group to provide a review and maintenance of all plant rooms servicing the accommodation. Dodd Group provide planned and responsive heating services for Local Authorities and registered social landlords throughout the UK, including over 80,000 properties across the midlands.

The brief:

Having identified potential issues caused by lack of effective water treatment and effective filtration, Dodd Group decided to carry out several system water tests from various plant rooms located at low level and in some cases, roof level, each providing heat to many apartments. The system water samples were sent to ADEY’s state of the art laboratory in Kent and tested against a variety of criteria including pH level, conductivity, molybdate, chlorides, iron, copper and aluminium.

System water quality was generally poor and frequently found to contain high levels of chlorides, aluminium, and iron, all of which indicated high levels of corrosion but also lead to high levels of black iron oxide, commonly referred to as magnetite, or sludge. This is harmful to heating systems and boilers, decreasing efficiency and leading to premature component failure, and needed to be addressed.

The solution:

A total of 50 system water samples were sent to ADEY’s laboratory in Sittingbourne as part of the project, one of ADEY’s three UKAS accredited laboratories in the UK. The lab provides fast, accurate and thorough reports for central heating and mains water, and a dedicated online portal can provide results and recommendations within 24 hours of receiving a sample. Following receipt of the water analyses, a structured system treatment plan commenced.

ADEY water test results showed that installation of the MagnaClean CMX™, a magnetic and non-magnetic sidestream filter available in different sizes, combined with water treatment chemicals and regular maintenance, would remove sludge and other non-magnetic debris, and help to maintain healthy and efficient heating systems for these plant rooms. Around 50 MagnaClean CMX units would be required.

“The comprehensive service provided by ADEY, from water testing to system and product advice, has enabled Dodd Group to source a complete plant room solution.”

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MagnaClean CMX® filters improve heating system reliability and reduce costs for UK Social Housing Schemes 7
1. Water colour after week 1 rotated

ADEY worked with Dodd Group and their selected merchant to ensure that the appropriate quantity and sizes of MagnaClean CMX were specified, sourced and available at the right time for each plant room. The merchant supplied all the filters and managed logistics to ensure that the work was able to progress without interruption. Like many plant rooms, space to retrofit an effective filtration solution was at a premium and so the decision to use CMX filters in a sidestream configuration was an easy decision to make. Flexibility in positioning and ease of installation of the unit within the plant room all proved to be a massive advantage for the contractor therefore the MagnaClean CMX Nano for the Primary Circuit and a MagnaClean CMX Midi for the Secondary Circuit were employed according to the demands of each system.

The MagnaClean CMX sidestream installation proved vital in this project as it was essential that the heating system operations were not disrupted, and tenants were not inconvenienced by any downtime.

During the first few weeks of the newly installed filter, due to the high levels of sludge in the system it was decided to fit the MagnaClean CMX filters without their filter cartridges, using just the magnets. By taking this simple action, it prevented the addition of CMX internal non-magnetic filter cartridges from being needlessly blocked with magnetite. Once magnetic capture rates reduced, cartridge filters/bags could be introduced to the filter housings to begin to capture non-magnetic system debris.

The project was able to continue seamlessly during Spring and Summer 2020 despite the added necessity of social distancing due to the COVID-19 pandemic, with ADEY, the merchant and Dodd Group operating within all necessary guidelines.

3. Solids removed at week 1 rotated
MagnaClean CMX® filters improve heating system reliability and reduce costs for UK Social Housing Schemes 8

The results

Following installation, the magnetic filters were initially checked and cleaned on a weekly basis as a significant amount of sludge was extracted from system water. Once capture reached an acceptable level, inspection frequency was reduced.

The heating systems varied in performance levels, though all have benefitted from the addition of MagnaClean CMX filters. Some displayed an extremely high level of system sludge, all of which has a detrimental effect on heating system efficiency, Co2 emissions and can lead to premature component failure.

The systems are now being protected by premium chemical water treatments which provide an advanced solution to long term preventative maintenance.

The social housing provider now have a way to ensure that sludge is captured and prevented from damaging these heating systems, knowing that monitoring and preventative measures are in place. This will in turn lower carbon emissions and limit future issues, reducing costs and inconvenience for both the Council and their tenants.


‘The comprehensive service provided by ADEY, from water testing to system and product advice, has enabled Dodd Group to source a complete plant room solution. Continued support throughout the project and the proactive collaboration between ADEY, the merchant and Dodd Group has meant that we have been able to improve heating system performance and reliability for the housing provider, which now contributes to lower heating costs and Co2 emissions, and improved tenant comfort.’ – George Dawson, Dodd Group

For further information about ADEY Commercial sealed system solutions, contact or telephone 01242 546 700