Fixtures, Fixture Fittings, and Water Heaters
Fixtures, Fixture Fittings, and Water Heaters
This domain tests fixture selection, installation clearances, fixture fittings, water efficiency, and safe water-heater installation. The exam expects you to know that fixtures must be approved, accessible for cleaning, securely supported, and installed so they can be used without cross-connection or backflow.
Core rules
- Water closets need clearance from side walls and adjacent fixtures, and usable space in front. Verify exact dimensions in the adopted code; common inspection failures are a toilet too close to a vanity or a door that swings into the fixture space.
- Fixture fittings include faucets, shower valves, flush valves, and supply stops. Shower and tub-shower valves must have pressure-balancing or thermostatic protection to limit scalding.
- Water heaters require a temperature and pressure relief valve, a discharge pipe of the same size as the valve outlet, gravity flow, no shutoff or trap, and termination at a safe receptor. A drain pan is required where leakage would cause damage.
- Thermal expansion control is needed when a heater is installed on a closed system with a backflow preventer or check valve.
Worked example
A 40-gallon electric heater is replaced in a basement. The installer connects a 3/4-inch T&P valve to a 1/2-inch copper discharge that runs 15 feet horizontally and ends 2 inches above a floor drain. This fails: the discharge is reduced, it has too much horizontal run and elbows for gravity flow, and the termination must be protected from freezing and sized to prevent injury. The fix is full-size pipe, minimal elbows, and a proper air gap above the drain.
Traps
Do not plug a T&P valve, reduce its discharge, or cap a drain pan outlet. Do not install a heater without expansion control on a closed system. Do not ignore fixture clearances because the fixture fits the room.