Antiscald shower valves prevent excessively hot water from burning the user. The Symmons line of antiscald valves is pressure-balanced to keep the hot-cold water mix at the same temperature level once the user has selected a comfortable temperature. An adjustment screw prevents the user from selecting a water temperature that would burn them. After installation, and if the house water temperature changes, you can adjust the temperature limit using a few tools.
Things You'll Need
Small, flat-head screwdriver
Loosen the handle screw located on the underside of the shower valve handle. Remove the handle from the spindle assembly to expose the spindle stem. Remove the two screws that hold the large, round trim piece on and remove the trim piece.
Take off the small, metal dome and gasket that cover the spindle assembly. This exposes the limit stop screw. Put the valve handle back on the spindle, without tightening the screw, and turn the shower on. Hold the thermometer bulb in the water flow to measure the water temperature.
Adjust the temperature of the water with the shower handle until the desired temperature is reached. Remove the shower handle from the spindle. Turn the temperature limit stop screw clockwise until it stops. Put the handle on the spindle and turn the water off. Remove the handle again.
Place the dome back over the spindle and place the dome gasket over the end. Put the large, round trim piece over the shower valve and install the two screws that hold it in place. Place the handle back on the spindle and tighten the handle screw.
According to The Wisconsin Department of Health Services, the maximum safe water temperature to set a faucet or shower valve is 110 to 120 degrees F.
Setting the water temperature above 120 degrees increases the risk of severe burns. At 140 degrees F, scalding burns can happen in as little as 6 seconds.