Is this venting of a tankless boiler correct?

Sink drain

How do I go from 1 1/4 P trap to 1 1/2 nut in the wall?

Are these the valves to turn off water for a bathroom sink?

The double sink has gone from slow drain to a halt. Plunging worked in the past but not this time. I've taken off the p-trap and I can see clear thru the horizontal to the T. I bought a 6ft hand auger, hit nothing and came out clean.

Slow draining shower. Does this little grate pop off with a screw driver?

I want to take this little grate off before I try to clean out my shower drain. Can I pop this off and back on again easily?

This doesn’t look right to me

The water in my apartment is so hot!! If I turn down this valve, will that help?

My shower is 104 when I turn it on just a quarter turn! I’m renting so I really don’t want to accidentally brake somthing so if I can have confirmation that turning this valve down (and to where) will help my situation!

Is 2” sufficient for this sump pump discharge line?

I have a narrow piece of property with a slight negative grade from the street - <1% in the front then 2-3% about mid-way to the back. I’m subbing out the construction of a 30” x 30” x 40” concrete sump pit (and electrical), but I will be doing all the Schedule 40 PVC piping to the pit from the downspouts and catch basins, buying materials this week. Sump pump will be a Zoeller M267. I originally planned on a 2.5” discharge line but the contractor that’s doing the sump pit notes and requests a 2”? The pit will be receiving water from 5 down spouts and various trench drains that will act as insurance during a heavy fast rain. I did calculations based on a 4” in one hour rainfall, and at maximum approx 34GPM would be dumping into the pit. Those numbers check out based on water area catchment maths but I wanted to see what you all thought in the real world. Other info: Rise from pit to curb drain is approx 1.5’ to 2.5’. Pump will be approx 125-135’ from curb drain. Pit and discharge line are green in the pic. Thanks for any help 👍🏽

Roommate poured a pot full of veg. oil down our kitchen sink (thinking it was water). What would you recommend doing in this situation? I thought I’d empty the p-trap in case any oil was caught but one side is glued, I see some cleanouts on the left but not sure what to do with that.

Shower mixing valve is leaking

Is there a particular type to replace this with?

Leaking Sink Sprayer Hose

The pull out sprayer hose on our sink started leaking today and we need to replace it. We can’t seem to find a hose with the right connector. I included a picture of the hose and connectors on both sides. The one on the left is what the sprayer was attached to and the one on the right is what plugged in underneath the sink.