Yes al lines under the slab should be min. 2 in. The vent on the sink is ok to be 1-1/2 since that sink is the only thing your venting tub vent can be 1- 1/2" also since you have a 2 inch vent on the toilet but it wouldn't hurt to be 2 in. your vent for the pump should be 2 in all the way thru the roof with nothing else tied into it. all the other vents can tie in together in the ceiling with 2 in going all the way to the main vent stack above the last fixture or thru roof. This can vary depending on your local codes so you might want to find someone in your area that is familiar with the codes.
I have the same setup, with this pump, 3" discharge and 2" vent, It works great 100%, and I would say this is the best way to do it.I'm surprised your vertical basin discharge pipe is 3". I thought those were usually 2" till they tied into the 3 or 4" gravity drained horizontal portion of the system. Won't a 3" vertical discharge pipe hold a substantial volume of waste that will drain back into the basin when the pump shuts off?
you are right they are usually 2 inch but the 3 inch will be ok as long as there is a check valve installed with 3 feet of the pump.I'm surprised your vertical basin discharge pipe is 3". I thought those were usually 2" till they tied into the 3 or 4" gravity drained horizontal portion of the system. Won't a 3" vertical discharge pipe hold a substantial volume of waste that will drain back into the basin when the pump shuts off?
That would leave 5 feet or more of 3" pipe full of water. When the pump cycles will it still push this left over fluid out? I have read so many different opinions about where to place a check valve, as well as which one is the best type to use.you are right they are usually 2 inch but the 3 inch will be ok as long as there is a check valve installed with 3 feet of the pump.
yes, I can confirm I have this setup with 5-6 feet of pipe above the valve,That would leave 5 feet or more of 3" pipe full of water. When the pump cycles will it still push this left over fluid out? I have read so many different opinions about where to place a check valve, as well as which one is the best type to use.