Why is the wet one and only hot or cold within one of my showers - no 'warm'? I have a single handle Sterling faucet, probably in the region of...

I have a single handle Sterling faucet, probably in the region of 15 years old. When I set the handle on 'Warm', it the faucet a moment ago spits out cold water. In order to win ANY hot water flowing, I have to turn it adjectives the way to 'Hot'. Then when I try to adjust it back to 'Warm' it is newly hot water - it never gets thaw. It's like my shower faucet has 2 temperature: HOT (SCALDING) or COLD. I have a second shower which is working just fine (thankfully) so I don't deliberate this is an issue with the hot water furnace. I am hoping this is something I can do myself. I have already changed out the cartridge contained by this faucet and it has not resolved the issue.
Run the water slower and agree to it heat up! Worked in my shower when a friend suggested it!


The faucet splits the distribution between the hot and cold pipes, so I would conjecture it could be the faucet is broken. there is a valve that mixes hot and cold, ironically, the mixing spout. It could be bad
Answers:    it may be time to replace your faucet, but if your lucky the temp.
setting on your water radiator could be set too high, try adjusting
to a lower setting..