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Extraction repair


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Established Member
4 Sep 2011
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I got a rude awakening this week from my 14 monthly COSHH test carried out by my Extraction Service Engineers. I did know that my filtration bags had been holed (I thought they were), well after 7 years I would expect some wear and tear. The issue was the fine dust was getting through the hole(s) so I thought and going into the cabinet and then leaking fine dust to exhaust flue. So I told the tester to bring some bags/tubes (cheap repair).

So he duly arrives and starts doing flow checks and by dinnertime was ready to shut down the system and do a filtration bag inspection and solve my leak. Well it seems water had been leaking in from the roof and sides of the Extraction unit. To let you understand my unit is outside, this is the first installation I have like this all my previous were inside a building. But due to noise/explosion it is now standard practice to do big installations on the exterior with the galvanised units we see all shiny next to joinery firms. This is not a problem as the unit panels are mastic sealed so no water access and egress. Now this is the bit I did not know, the service guy stated the unit should last 10 years without reseal. In my case and my location it seems this lasted 7 years. The water damage had seeped on to the filtration bags and they were not holed but the sewing thread had given way. Me thinks inferior bags used by installer as these should last longer as being rip proof and the thread should never give way well the ones I used previous. So now the rub, cost of repair due to water and complete fit out of filtration tubes, sealing panel joints and foil bitumen the roof and I think over £6k will be needed.

So in hind sight checking mastic and seals should be a matter of routine from now on. I did fit new auto dampers last year to the system for power savings, it does seem this aids in tube wear and tear as it runs under full capacity. The other point I found out is replacing single tubes is not an option as dust will filter through the new tubes more and not a even spread over all the tubes in my case 20 tubes per unit so the need to replace all tubes in my case with the cost this involves.

A lessen learnt.