I have a NCB 250/150H combi-boiler unit for space heating and domestic hot water and I noticed there's black sludge build up in the condensate neutralizer over time. I've flushed DHW with vinegar, cleaned out the filters, and replaced the neutralizer media fairly recently, but seems that the build just accumulates over time. Should I be a concerned? enter image description here

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  • How is that mounted? Can you take a picture of the whole setup?
    – Matthew
    Commented Apr 22 at 0:20
  • It’s mounted onto the wall using clips provided by neutralizer kit. I’ve added an additional picture showing the mount and connections
    – Steve
    Commented Apr 22 at 1:26
  • You're installed improperly. The outlet should be "up" so that it's higher than the inlet. Whether this leads to the buildup can't say
    – Matthew
    Commented Apr 22 at 3:37


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