Washer drain-- Did plumber do this right?

I had a plumber install a floor drain and washer standing pipe in my basement in order to relocate my laundry. The floor was dug up and tied into the main drain for the house. The tie in was branched with each branch p-trapped separately and one leading to the floor drain and the other the washer drain. The concern is there is no vent pipe (it's about 8' downstream from the main stack). The distance from the main drain tie-in to the branch is maybe 2-3 feet. The floor drain then p traps right off the branch. The washer line branch extends another 2 feet before another p trap then straight up about 3 feet above the floor. All pipe is 3". Does this sound ok?

You likely need a 2" vent. Most main drains are not set up to vent all fixtures in houses.

the short answer is no]
the long answer is nooooooooooooooooo
you need a vent

drains

Who said the installer was a plumber? That is not the correct way to do it. The way the drain is installed determines whether it needs a vent or not, not the distance from something else. Using a 3" pipe overcomes some problems, but it is a bandage, not a cure.

Prolly the same plumber what piped that solar tank

Thanks guys for your answers. I was afraid this was going to be the concensus. The guy came recommended so I just assumed he was the real deal. Hj, can you give me an example of an drain installation that would not require a vent? Maybe I'm not describing it well enough. If there is just no 2 ways about it, what size would the vent need to be (thinking about how it can be routed from the basement to the roof)? Also, If a vent does need to go in, could a utility sink drain be added off the 3" standing pipe-turned-vent (assuming this would be the way to handle it)? At least then it wouldn't feel like a complete redo. Thanks again for the advice.
EDIT: oops, nevermind the vent size question, FL orange answered this already.