An extractor fan I fitted has been shorting out due to water ingress. I insulated the duct and sealed the fan to the duct, as well as the cable entry, with putty. But the problem has not gone away. I have now removed the fan as I am concerned about the danger of water on the electrics, and my customer was obviously not happy about the lights tripping out all the time.
Now I have asked the customer to get the (possibly asbestos) duct removed so I can fit a moisture trap and new duct. I had planned to fit flexible duct as I am more confident about sealing this effectively to the fan, having used it before. But now I find you can't buy moisture traps for flexible duct.
So that leaves me with several questions: if I was to fit a short length of rigid duct between the fan and trap, and then another short length above the trap, taped to insulated, flexible duct, would this work? Or would the water drip from the folds of the flexi-duct right through the trap, missing the drain? How would I support the rigid duct? And how would I drain the trap, given that there is no access to soffits (dormers and coombed ceilings), and thick stone walls several floors up which cannot feasibly be drilled. The existing duct rises nearly vertically about 1.5m from the ceiling mounted fan to the roof vent.
Would it be a better idea to fit an inline fan close to the roof vent? How close can it be without risk of freezing due to outside temperature? Any other problems with this approach?
Any help would be so much appreciated. I've found a lot of threads, including some on here, about similar problems, but most relate to very long runs and flexible ducts with low points etc, none of which apply here. I'm not really sure why the condensation problem is so severe (fan swimming after only a day or two), with a short, now insulated duct.
Sorry for such a long post, thanks for reading, even if you can't help.
Now I have asked the customer to get the (possibly asbestos) duct removed so I can fit a moisture trap and new duct. I had planned to fit flexible duct as I am more confident about sealing this effectively to the fan, having used it before. But now I find you can't buy moisture traps for flexible duct.
So that leaves me with several questions: if I was to fit a short length of rigid duct between the fan and trap, and then another short length above the trap, taped to insulated, flexible duct, would this work? Or would the water drip from the folds of the flexi-duct right through the trap, missing the drain? How would I support the rigid duct? And how would I drain the trap, given that there is no access to soffits (dormers and coombed ceilings), and thick stone walls several floors up which cannot feasibly be drilled. The existing duct rises nearly vertically about 1.5m from the ceiling mounted fan to the roof vent.
Would it be a better idea to fit an inline fan close to the roof vent? How close can it be without risk of freezing due to outside temperature? Any other problems with this approach?
Any help would be so much appreciated. I've found a lot of threads, including some on here, about similar problems, but most relate to very long runs and flexible ducts with low points etc, none of which apply here. I'm not really sure why the condensation problem is so severe (fan swimming after only a day or two), with a short, now insulated duct.
Sorry for such a long post, thanks for reading, even if you can't help.