Originally Posted by TenOC
...The problem is RV related....
Our shower has the single knob that you turn. It starts out cold and as you turn the handle more it gets warmer.
When we first got the camper, no matter what we did the shower never got "hot". It was always just luke warm. I figured it was the way the shower knob handle was mixing the hot and cold.
As we purchased our camper in the Fall of the year and used it immediately, the outside weather was starting to dip colder. So the water in the fresh water tank, and even from the shore water spigot was very cold. The water heater was HOT. The kitchen stand alone hot water side was HOT. So, I knew it was the mixer at that knob.
I tried everything I could think of to get the water hotter at the shower. But nothing practical worked. Then the idea hit me.
I pulled the handle / valve / mixer from the wall and simply switched the hot and cold lines in the back of the faucet handle thing.
Now, when the water is first turned on, it's all hot instead of all cold. When the handle is turned all the way around, it's pretty cold! But not ice cold. So, it's working just the opposite.
There really is no problem getting burned or anything from 140 degree water, because when the faucet is first turned on now, it still takes about 15 seconds or more for the cold water in lines to get replaced with the hot water from the water heater. So, there's really no danger of getting scaled. And if the handle is turned a bit more when first turning on, it mixes with cold (initially, cold and cold) until the hot water line purges the cold out. This give us plenty of time to adjust the water temperature.
If we have guests (like our son and grandson), we always instruct them that it's HOT first and the farther it's turned it gets colder. No one has ever been burned.
So, it's possible your mixer at the faucet(s) are messed up.... or you may find a better resolve by switching the hot and cold line that attaches to that faucet outlet.
For us, this was the best solution. We didn't have to purchase a new handle "thing". Personally, I prefer 2 handles, a hot and a cold. I hate those single handle faucets. My kitchen sink is the same way, single handle. But, HOT is HOT and Cold is Cold. I still hate the thing.
The nice thing about my change now is, we do our fair share of cold weather camping, and incoming water is ALWAYS very cold. No matter how cold the incoming water is, the shower is always HOT now, no matter how cold the incoming water is. It just, when the incoming water is really really cold, it doesn't take much cold to mix with the hot to keep it a comfortable 100 degrees for showering.
In the heat of the Summer the incoming water always much warmer, sometimes as much as 70-75 degrees, depending on the water source. Then it takes very, very little hot to keep it at that same 100 degree comfortable temperature. So, the handle has to crank around farther to make it cooler as it takes more cold volume when the cold line is much warmer (in the Summer).