No wye valve here either. The purpose of the wye fitting setup is to allow the pump out hose and macerator hose to use the same holding tank draw tube, which I'm sure yours has one, too. It's the only way it will work as the pump out hose connects to a fitting at the top of the tank.
Regarding your macerator pump. What happens when you turn it on? Does it run, but not pump or not run?
Funny story
When I bought my Hunter 40.5, it didn’t take long to fill the single holding tank with 2 heads, and 2 kids.
No guage on the tank. You knew it was full when the vent overflowed. Yuk.
Went to pump it out. Ran the pump out, and in about 10 seconds, it stopped pulling “stuff”
I knew that there was no way that the tank was emptied that quick
Put a hose into the deck fitting, and it overflowed (another Yuk), in 10 seconds.
Tried pumping out again. No luck
Called Hunter. They said, are you sure the pump out is working???
I went to another pump out. Same story.
Had to pull the tank. That was scary, as it was full.
Turns out, the goof that welded in the dip tube didn’t read the drawings correctly, and instead of welding it facing down, it went horizontal .
So, it literally pumped out the top 3 inches of the tank
Hunter scrambled to get another tank, and shipped it up to Toronto.
So,,, tanks are supposed to have the tube going to the bottom. Mine was a “special version”