My husband and I are planning on remodeling the kitchen of our 1960's cape cod. It has been remodeled a couple of times by previous owners, so, as a start, we are peeking into walls, soffits, etc to see what will be easy and what won't be. We are not certain, but we do not believe the latest remodel was permitted, as we have found a number of questionable things thus far in our explorations.

There is currently an old double wall oven which is in a location we are planning on keeping. It is, however, set into drywall instead of cabinetry, which we would like to change. Upon inspection of one of these oven "walls", we have found a plumbing stack/vent and also the cleanout. It would seem that we would have to remove the wall oven to access the clean-out. Only the kitchen sink now drains into this, though it looks as if a laundry tub and washing machine once did too (the previous owners moved the laundry to another room in the house).

My question is, is this to "code", to have a plumbing vent/stack (cast iron at bottom, then galvanized steel from about two feet up) right next to an oven? I would guess it has been like this for at least 30 years, as the double wall oven is an ancient Thermador model. Thank you for any help you can provide.