Järnet housing cooperative flats Lower maintenance costs and more comfortable living with effective air and magnetite separation.

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The Järnet housing cooperative runs the 204 HSB flats at Gruvgången 71 in Karlstad. The flats are divided between two blocks built in 1964. District heating from Karlstad Energi supplies both blocks with heat through a shared substation.
The challenge
In the cold months, complaints from residents about cold rooms and flats were an everyday occurrence for Jonas Holm, chair and building manager for the Järnet housing cooperative. “One year we had to enter 47 flats to ‘exercise’ radiator valves that were not delivering the correct fl ow,” says Jonas. The cost of emergency call-outs from HSB’s maintenance engineers was running at SEK 11,000 a year. It turns out that there were large amounts of magnetite in the system. Magnetite is a naturally magnetic iron oxide frequently found in water-based heating and cooling systems. The magnetite was collecting in the radiator valves, preventing them doing their job.​
The solution
HSB’s energy consultant in Karlstad, Peter Persson, advised Jonas to install an air and magnetite separator in the system to deal with the problem. Jonas got in touch with IMI Hydronic Engineering for help with product selection. The Zeparo ZIK, a combined air and dirt separator with magnetic add-on, was installed in the substation for the two blocks. Zeparo removes air, micro bubbles and sludge from water systems. Magnetite is removed by a magnetic rod at the centre of the separator. The rod attracts the magnetite, which can then easily be emptied from the separator. The total investment cost including installation was SEK 47,000.
The outcome
Jonas is pleased with the result. He takes us to some PET bottles containing samples showing the magnetite content before and after a Zeparo was installed. The evidence is clear, and the system is now working as it should. No extra service call-outs are necessary to deal with jammed radiator valves. “Our costs are lower now. But more importantly, the living conditions are more comfortable, with no more complaints from residents,” says Jonas. This success story has left them wanting more, so according to caretaker Stig Aronsson, they are going to do the same thing in two neighbourhood associations in Gräsdalen.
Our costs are lower now. But more importantly, the living conditions are more comfortable, with no more complaints from residents. - Jonas Holm, chair and building manager for the Järnet housing cooperative 

Facts
Project type Apartments
Building Järnet housing cooperative flats
Location Gruvgången 71, Karlstad, Sweden
Consultant HSB energirådgivning
Owner BRF Järnet
Products Zeparo ZI/ZE​

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