I just installed a new electric water heater myself (done it before but I realize this was probably my error somewhere along the lines) and it only puts out warm water. I made sure that there was no more air in the lines when I turned on the power and the top pipes are still hot (not burn me hot, but maybe really really warm). I was next to it for like 30 minutes after power went on and I didn't hear any pops.

I changed the temperature on the top thermostat and it started putting out hot water like I'm used to, but after a day or so it went back to just being warm.

I didn't check the bottom thermostat though purely because I can't open the panel. It seems like the threading that's hanging onto the screws is detached from the inside of the heater so it just spins and spins and spins and doesn't tighten/loosen.

I read another thread here and someone suggested they're running a 240 V heater on 120 V and I have no idea if my old one was 120 V since it's gone already. Is there any other way for me to tell? It is hooked up to a double pole breaker.

And is there any way to get that bottom panel off that I'm not thinking of (short of hacking it off)? I feel like the water should be hot enough on default settings but it just bugs me that I can't open up the bottom thermostat and look.