Do you have a bath faucet that absolutely does not run you a hot enough bath? Or maybe a shower faucet that seems to delight in scalding you when you accidentally bump the control lever with your elbow? You can fix these types of problems by adjusting the maximum temperature of the faucet. Doing so requires only basic tools, and in most cases only takes a few minutes of trial and error to get your shower faucet running the way you want it.
A Quick Lesson on How the Levers Work
Most single lever shower faucets are designed to have up to 270 degrees of rotation. At about 45 degrees from the "off" position, the cold water is fully on and the hot water is still off. As you continue rotating, the hot water starts to come on until, at about 135 degrees of rotation, both the hot and cold water is on full. From this point, the hot stays on and the cold is gradually turned off until, at 270 degrees, the hot water is fully on and the cold water is fully off.
The mechanism inside a single lever faucet is adjustable and can be moved so that it limits the amount of rotation. Remember, it's at the full 270 degrees of rotation that you only have hot water. At less than that, cold water is still mixing in. If you can't rotate the lever a full 270 degrees, cold water is always mixing with the hot. The shorter the maximum rotation is, the more cold water is being added and the cooler the faucet's maximum temperature.
Look Under the Handle
To adjust your shower faucet's temperature, take the lever or handle off. In most cases, you can easily pry out a piece of metal or plastic on the front of the faucet handle to get at the screw that holds the handle on. Some handles have a hole hidden on the underside; you can use a small screwdriver or Allen wrench to remove the handle. Once the handle is off, you should see a collar with a little plastic nub that sticks up. When the handle is in place, it's this nub that stops the rotation at the "maximum hot" position. Look inside the handle or slide it back into place and turn the faucet on and off to help visualize how this works.
Some collars have two pieces. On the back piece, the nub is always at the 12 o'clock position and the other piece can be pulled out and rotated clockwise from the 12 o'clock position and reinserted. The farther clockwise from 12 o'clock, the more the lever's rotation is limited and the colder the maximum temperature. On other collars, there is an adjustment screw that can allow for some adjustment of the collar. Remember that pushing the nub clockwise means a cooler maximum temperature.
Older single lever faucets may have hot and cold adjustment screws instead of a collar. To increase temperature, turn the hot water adjustment screw counterclockwise or the cold water screw clockwise. To decrease the temperature, do the opposite. The key to proper adjustment is to experiment and test--trial and error will get you there.