I have a Kenmore micro/ hood combo and I want to convert it to vent outside instead of re-circulation. The only way is to run it through the cieling and out the back of the house which is a 15 foot run. It will have one 90 at the cieling. I can not find the recommendation for how long the duct can be. Is there a general rule. It has grease filters so I don't think that's an issue....can anyone shed some light on this..
I found a website ehow that state the manuf recommends no longer than 140 linear feet. I can't believe that. That's outrageous. Wouldn't that cause a veal load of condensation in the duct. I mean I'm only going 15 feet with a max 3 ft drop to the unit.