PC PC Fixture & Appliance Installation 1 — Questions and Answers
Question 1: When setting a toilet flange, at what height relative to the finished floor should the top of the flange be positioned?
- 1/4 inch below the finished floor
- Flush with or up to 1/4 inch above the finished floor (Correct answer)
- 1 inch above the finished floor
- It does not matter as long as the wax ring seals
Correct answer: Flush with or up to 1/4 inch above the finished floor
The toilet flange should be set flush with or up to 1/4 inch above the finished floor to ensure a proper wax ring seal and prevent rocking.
Question 2: What type of supply connection is required between a gas water heater and the gas supply line to allow for vibration and movement?
- Rigid black iron pipe
- CSST flexible gas connector (Correct answer)
- PVC tubing
- Copper compression fitting
Correct answer: CSST flexible gas connector
A CSST (corrugated stainless steel tubing) flexible gas connector is used for the final connection to a water heater to allow for movement and vibration without stressing the connection.
Question 3: When installing a pedestal sink, what must be done to properly support its weight?
- Attach it only to the pedestal base
- Anchor the basin to a wall-mounted blocking or carrier (Correct answer)
- Rest it on the floor only
- Glue it to the wall with construction adhesive
Correct answer: Anchor the basin to a wall-mounted blocking or carrier
Pedestal sinks must be anchored to wall-mounted blocking or a carrier installed in the wall during rough-in to bear the weight of the basin and user.
Question 4: What is the purpose of the pressure-temperature (P&T) relief valve on a water heater?
- To regulate incoming water pressure
- To prevent the tank from over-pressurizing or overheating to dangerous levels (Correct answer)
- To balance hot and cold water temperatures
- To measure the water temperature at the fixture
Correct answer: To prevent the tank from over-pressurizing or overheating to dangerous levels
The P&T relief valve automatically opens to release water if the tank pressure exceeds 150 psi or temperature exceeds 210°F, preventing explosion.
Question 5: When connecting a dishwasher drain hose, what installation technique prevents wastewater from siphoning back into the dishwasher?
- Installing a check valve at the dishwasher pump
- Creating a high loop or installing an air gap at the counter (Correct answer)
- Using a larger-diameter drain hose
- Connecting the drain directly to the P-trap
Correct answer: Creating a high loop or installing an air gap at the counter
A high loop or air gap prevents backflow by keeping the drain hose elevated above the flood level rim, preventing siphoning of dirty water into the dishwasher.
Question 6: What is the standard rough-in height for a wall-hung lavatory supply stop valve from the finished floor?
- 12 inches
- 21 inches (Correct answer)
- 24 inches
- 36 inches
Correct answer: 21 inches
Supply stops for wall-hung lavatories are typically rough-in at 21 inches above the finished floor to align with standard lavatory supply connections.
PC PC Fixture & Appliance Installation 1
When setting a toilet flange, at what height relative to the finished floor should the top of the flange be positioned?