Yet another washer/laundry tub project

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New Member
Jun 6, 2018
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Nova Scotia, Canada
I am installing drains for a washing machine and laundry tub in the basement of my 90 year old home. The existing waste stack is 4" cast iron. There is a 4" wye where the stack exits the building beneath the basement floor. All of the drains from the upper floors feed into this stack. The previous owner installed a 3" ABS san tee into the branch of the wye with a 3” clean out and a 1.5” drain for a washing machine, and I want to replace this arrangement using the attached plan. With the exception of the 4” c.i. waste stack and 4” c.i. wye, everything in my plan will be ABS and exposed. There is no access to a vent from the basement without major deconstruction.
My questions:

1. As there is no access to a vent, I designed the plan with an AAV. However, as the entire setup is within 5’ of the waste stack, can I direct vent into the waste stack and not use the AAV?
2. Is the 3” clean out on the waste stack okay or should it be 4"?
3. Is the clean out required on the horizontal branch (marked A)? Can I roll the wye on to its side?
4. Is the wye (marked B) okay or should that be a combination tee wye?

Much appreciation for reviewing my plan and comments or suggestions.