Installation and Maintenance of Plumbing Fixtures and Appurtenances
Fixtures and appurtenances
This domain tests setting, connecting, testing and maintaining water closets, lavatories, sinks, urinals, floor drains and their valves and traps. Exam items often describe a leak, a loose fixture or a repeated service call and ask for the correct cause or repair.
Core rules
- Check the rough-in dimensions and fixture schedule before setting a fixture; confirm the drain, supply and vent locations match the drawing.
- Set fixtures level and secure. Use a new wax ring or approved seal on a water closet, align the closet bolts and tighten alternately until snug; over-tightening cracks porcelain.
- Connect the supply through an accessible shut-off valve; use escutcheons at finished walls and floors.
- Fit the correct trap to each fixture and maintain the trap seal; a floor drain may need a trap primer.
- Test after connection: open the stop, fill the tank or fixture, check supply and drain joints, flush and observe.
- Maintenance: isolate and drain before repair; replace washers, cartridges, flappers and fill valves with matching parts; clean strainers and aerators; check for hidden leaks.
Worked example
Install a water closet. Reasoning: confirm the closet flange is level and fixed; clean the flange; place a new wax ring; lower the bowl with the closet bolts through the base; tighten the nuts alternately and only until snug; connect the supply to the stop; open the stop and fill the tank; set the water level to the marked line; flush and check the tank, bowl and supply joints for leaks; only then finish the base.
Traps
Reusing a wax ring, over-tightening closet bolts, omitting the shut-off valve, caulking before testing, and forgetting the trap primer on a floor drain are common errors. A fixture that drains slowly may have a partially blocked trap, not a faulty fixture.