Here is the installation diagram from the manual for the Liberty 404 drain pump. It clearly states "Note: a trap shall be used between the fixture and pump, a flange type is recommended."
Will the s-trap be siphoned out, leaving the sink and washer stand pipe vulnerable to nasty pump basin smells? I can't figure out if the outside air vent on the side of the pump basin will somehow brake the siphon. Im thinking no, since the trap vent should be above the trap weir but the fact that its draining into a vented pump before being discharged into the sewer line is confusing me.
Will the s-trap be siphoned out, leaving the sink and washer stand pipe vulnerable to nasty pump basin smells? I can't figure out if the outside air vent on the side of the pump basin will somehow brake the siphon. Im thinking no, since the trap vent should be above the trap weir but the fact that its draining into a vented pump before being discharged into the sewer line is confusing me.