Planning to install a washer with 25gal drum capacity that has no discharge pump but is designed to drain by gravity with chek valve into three inch floor drain. Problem: no floor drain available only 1 1/2 inch standpipe. Three inch vent stack is available in wall nearby. Has been suggested that I place new three inch pvc drain line (with p-trap) from machine to the vent stack directly as alternative. Height of machine drain output is such that it would be lower than the ~18inch height of the 1 1/2 inch drain for old washer furthermore it would require a reducer from three inch pipe down to 1 1/2 inch. So, options are as above or concrete saws and room demolition to install floor sink. Any other suggestions or problems with what was recommended?
Thanks in advance