How to adjust anti scald valve on american standard shower faucet

Remove the handle,and all the trim rings,and the cartridge cover. take a flat head screwdriver and use it to lift
up the red ring behind everything, this is the hot limit safety stop,
this just stops the handle from turning to full hot.

Once you have the red ring lifted up, notice the numbers and the pointer
on the ring, numbers are on the fixture,

O= hottest 7=cold

See what the ring pointer is set to now, and move it half, before you put this back together, just set the handle on the unit and run the water to see if its to hot or not enough. Once you have found what is the best setting, then replace all covers and trim, handle.

We have a recurrent problem with our anti-scald valve, in that from time to time (at about monthly intervals) it will supply only cold water to the hot line.

I found that shutting off the cold supply to the water heater, and then draining off about half gallon of water from the bottom of the tank, with a sharp rap delivered to the anti-scald valve prior to restoring the cold supply to the tank , takes care of the problem (till the next time). I
Its quick, cheap, easy and works for us.

You may have to remove the valve and clean it the cold water side may be plugged up causing it not to allow enough cold water to go threw the facet.