Shower temperature. Help with a puzzling matter

[Jkarnaki]

Ever since I moved to this new place the shower temperature (in both rooms) was relatively low and did not last long enough.
I did notice that the water in the sink is hotter usually, but I thought this might be normal (weaker flow) OR that there is something specific to the shower vavles.
Landlord sent someone to check the water heater, and they said thermostats were bad and replaced them.
Now the shower temp is MUCH lower after this. I am talking about barely making it to 90F. However the kitchen faucet can go up to 105F.

I am puzzled, if it is a shower valve issue why would messing with the water heater affect it? At the same time, if it is a water heater issue why would the faucets have decent temperature (105F)?!

Any thoughts please?

 

[LLigetfa]

Some jurisdictions use tempering valves at some fixtures to prevent scalding. Dish washers are often exempted from such anti-scald codes.

 

[Sponsor]

 

[Reach4]

At the same time, if it is a water heater issue why would the faucets have decent temperature (105F)?!

Maybe there is some cooling after the water leaves the showerhead and before the container where you are measuring the water temperature. Maybe the path to the shower is much longer.

Is there some gadget at your water heater that connects to the hot and cold (a mixing valve)?

 

[Cacher_Chick]

Many newer shower valves have an adjustable stop to prevent people from scalding themself. Identifying what valve you have may be a good place to start.

 

[Terry]

Many newer shower valves have an adjustable stop to prevent people from scalding themself. Identifying what valve you have may be a good place to start.

A single handle often has a limiting stop to prevent rotating to full hot. With an electric water heater set low, there is no need to limit it down even further. Most new water heaters come preset to 120 degrees, same as tankless for gas. I would check for the setting behind the handle first.