PC Installation Techniques 3 — Questions and Answers
Question 1: When connecting a gas dryer to a flexible gas connector, what is the maximum allowable length of the connector?
- 3 feet
- 6 feet (Correct answer)
- 8 feet
- 10 feet
Correct answer: 6 feet
Flexible gas appliance connectors are limited to a maximum length of 6 feet by ANSI Z21.24 and most fuel gas codes to limit risk in case of damage.
Question 2: A 3-inch sanitary tee is being installed in a horizontal drain line. Which direction must the branch outlet face?
- Horizontally, at 90 degrees to the run
- Downward, toward the floor
- Upward, toward the ceiling (Correct answer)
- At 45 degrees in any direction
Correct answer: Upward, toward the ceiling
A sanitary tee installed in a horizontal drain line must have its branch facing upward (vertical) to serve as a vent connection; it cannot be used for a horizontal drain branch.
Question 3: What type of flux is recommended for use with lead-free solder on potable water copper pipe?
- Acid flux (zinc chloride)
- Petroleum-based flux
- Water-soluble lead-free flux (Correct answer)
- Rosin flux
Correct answer: Water-soluble lead-free flux
Water-soluble, lead-free flux is required for potable water copper pipe connections to comply with the Safe Drinking Water Act and avoid contaminating the water supply.
Question 4: When installing a water heater in a garage, the ignition source of the water heater must be elevated a minimum of how many inches above the floor?
- 6 inches
- 12 inches
- 18 inches (Correct answer)
- 24 inches
Correct answer: 18 inches
Water heater ignition sources in garages must be elevated at least 18 inches above the floor to keep them above potential accumulations of heavier-than-air flammable vapors.
Question 5: Which tool is used to expand PEX-A tubing ends before inserting a fitting?
- PEX crimping tool
- PEX expansion tool (expander) (Correct answer)
- Compression sleeve tool
- Tube cutter and deburring tool
Correct answer: PEX expansion tool (expander)
PEX-A uses the expansion (ProPEX) method where a special expansion tool expands the tube and fitting ring before the tube contracts back to grip the fitting.
Question 6: What is the minimum distance a vent pipe must extend above a roof surface that receives no snow load?
- 3 inches
- 6 inches
- 12 inches (Correct answer)
- 18 inches
Correct answer: 12 inches
Most plumbing codes require vent pipes to extend at least 6 inches above the roof surface to prevent rain and debris from entering the vent, though 12 inches is the common standard requirement.
Question 7: When soldering copper fittings, at what point should solder be applied relative to the torch flame?
- Apply solder directly into the flame to melt it
- Apply solder at the same point as the flame
- Apply solder to the opposite side of the joint from the flame (Correct answer)
- Apply solder before heating the fitting
Correct answer: Apply solder to the opposite side of the joint from the flame
Solder should be applied to the opposite side of the joint from the flame; when the fitting is hot enough, capillary action draws the solder completely around the joint.
PC Installation Techniques 3
When connecting a gas dryer to a flexible gas connector, what is the maximum allowable length of the connector?