Does older ovens have vent pipes?

My kitchen was recently demolished and had someone came and removed all the appliances and cabinets.
Above the stove top there is a range hood which has a galvanized 4" vent pipe that exhaust to the roof.
About seven feet over there is another galvanized vent pipe, same size that goes through the roof but I have no idea what it is for. They have already demoed everything and they didn't remember what it was connected to. But the location of it was where there used to be a double oven. Oven was 35 years old brand was Thermatronic by Thermador. Does an older oven need a 4" exhaust vent? or may be it was an abandoned old vent that was not connected to anything.
Another question. We also removed a huge refrigerator brand name Subzero also 35 years old. This monster has a copper pipe connected to it's back and it is not an ice maker supply feed. It routed into the wall, followed the bottom plate and exited the house, on the outside is a trap and stopped. It almost look like a normal air conditioning condensation drain line, but from a refrigerator? I have owned a dozen refrigerator and never seen one that needed a dedicated drain line.
May be I am just ignorant of these old old appliances. I want to make sure I am doing this right.
Thanks,
MC
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Almost all Refrigerators have defrost drain lines which are piped to a Condensate drain pan on top of the compressor or electricaly heated. However some of couse lead to a trap and outside drain

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Hard to say, but if it is very ood, it may have had an oil fired heater in the stove at one time.

Sub Zero is still a top unit, well made (and expensive) It would not surprise me that they used a drain line instead of the pan the typical household unit has. They have a commercial quality line.
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MiamiCuse wrote:

it is (or was) common for gas wall ovens to be vented through the roof in a manner similar to gas water heaters. It's nice in the summer to be able to cook a roast in the oven without heating the kitchen.
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