We have almost nothing oil-fired out here so I’m not that familiar with the Oil-fired heating appliances. They can have direct vents too, right?
Kenton, here are the installation manual on a popular brand up here.
Buderus Model Oil fired.
http://www.buderus.net/Portals/16/115scim%20G115%20Direct%20Vent%20Manual%201206.pdf
Hope this helps.
Marcel
Thanks Marcel.