I have not run the Darby on a power vent but I do run a Fraanco Belge in the shop with one. I have a CO alarm that I test when I go in the shop if the stove is running and I am not sleeping/living there so I really don't care if the place fills with CO when I am not there.
This is very bad advice, I'm surprised no one else has commented on it. If the building is full of carbon monoxide from a failed power vent and you walk in there you might very well be unconscious before you figure out what's going on, working CO detector or not.
A hand-fired appliance should never be connected to a power vent.
It's not worth it, take no chances.