Fixtures & Appliances — Plumber (306A) Practice Questions

Free Fixtures & Appliances practice questions

1. 1.A water closet requires a minimum drain size of:

   • A.2"
   • B.3"✓
   • C.4"
   • D.1-1/2"

   Why: Water closets (toilets) require a minimum 3" drain. The closet bend connects the flange to the 3" branch drain. This is a non-negotiable code requirement.

2. 2.An anti-scald valve on a shower is required to prevent water temperature from exceeding:

   • A.38°C (100°F)
   • B.49°C (120°F)✓
   • C.60°C (140°F)
   • D.No requirement

   Why: Anti-scald (thermostatic mixing or pressure-balanced) valves are required on showers/tubs to limit output to 49°C (120°F) maximum, preventing scalding injuries.

3. 3.What is the rough-in measurement for a standard water closet?

   • A.10"
   • B.12" (305mm) from finished wall to centre of closet flange✓
   • C.14"
   • D.8"

   Why: Standard rough-in is 12" (305mm) from the finished wall to the centre of the closet bolt holes. 10" and 14" rough-ins exist but are less common.

4. 4.What type of valve is required for a water heater?

   • A.Gate valve only
   • B.Temperature and Pressure (T&P) relief valve✓
   • C.Check valve only
   • D.Ball valve only

   Why: T&P relief valves are life-safety devices. They open if temperature exceeds 99°C (210°F) or pressure exceeds 1035 kPa (150 PSI), preventing tank explosion.

5. 5.An indirect waste connection means:

   • A.Pipe connected directly to the drain
   • B.A drain that discharges through an air gap into a receptor (no direct physical connection to the sewer)✓
   • C.A hidden drain
   • D.A temporary drain

   Why: Indirect waste uses an air gap between the fixture drain and the receptor (floor drain, floor sink). Required for food equipment, ice machines, HVAC condensate, and similar to prevent backflow.

6. 6.When mounting a wall-hung lavatory, the carrier must support:

   • A.Just the sink weight
   • B.The sink plus a person leaning on it — typically rated for 200+ lbs✓
   • C.Only water weight
   • D.No structural requirement

   Why: Wall-hung fixture carriers must be structurally secured to framing and rated to support the fixture plus applied loads (someone leaning/sitting on it). Carriers bolt to the wall structure.

7. 7.Accessible (barrier-free) fixtures must comply with:

   • A.No standards
   • B.CSA B651 and local building code accessibility requirements for height, clearance, and controls✓
   • C.Only aesthetics
   • D.Only commercial codes

   Why: Barrier-free fixtures: specific mounting heights, clear floor space, knee clearance, lever handles (not knobs), and insulated P-traps per CSA B651 and local accessibility codes.

8. 8.When installing a water heater, the cold water inlet must have:

   • A.Nothing special
   • B.A shut-off valve for isolation and a dielectric union if connecting dissimilar metals✓
   • C.Only a check valve
   • D.A PRV

   Why: Cold inlet needs: a shut-off valve (isolation for maintenance), and a dielectric union if connecting copper to steel nipples on the heater. Also required: T&P valve, expansion tank if closed system.

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