Module 2 Review Questions Plumbing Flashcards
What are 3 things that go wrong with water supply?
pressure or flow is insufficient; leaks; dirty water
Evaluating the quality of the water available at a private source is beyond the scope of a standard home inspection. T/F
True
List 6 materials commonly used for water service piping.
copper, lead, PVC plastic, CPVC plastic, galvanized steel, brass, cast iron
What is the typical minimum diameter of water service piping in modern construction?
3/4 in
What is the function of a stop and waste valve?
stop and waste valve shuts off water supply & allows the system plumbing to be drained
List 5 materials used as water supply piping.
copper; brass; stainless steel; polybutylene, CPVC; polyethylene
When was copper supply piping first used?
a. 1850s
b. 1900
c. 1930s
d. 1960s
e. 1990
1930s
At what interval is vertical supports for copper piping?
at least every 10 feet, or every floor
What is the recommended horizontal spacing of supports for copper piping?
every 6 to 10 ft
What is the recommended horizontal spacing of supports for galvanized steel piping?
10 to 12 ft
Plastic piping needs less support than copper piping because it tends to expand more. T/F
False
What is the implication of improper support on piping?
implication of improper support is leakage
Briefly describe a cross connection.
a cross connection is a piping arrangement in which waste can back up into the supply piping & contaminate it when the pressure drops on the supply side.
List 5 locations in a house where there may be a cross connection.
- Fixtures where the faucet spout is below the overflow or flood rim of fixture
- Fixtures where hand held showers, extendable faucets or vegetable sprayers can be left in tubs, basins, or sinks
- Garden hoses attached to a hose bibb
- Toilet tank where the fill water enters at the bottom
- A water softener
Is a vacuum necessary to have backflow at a cross connection? Y/N
No
Briefly describe water hammer, & why it occurs.
Water hammer is a loud banging sound in the pipes. Water hammer occurs b/c water moving at several feet per second has to stop abruptly when a valve is turned off. The water bounces off the valve & creates a vacuum as it bounces away from the valve. The vacuum then violently attracts the water back to the low pressure area and the water again bounces off the closed valve. The effect of this is a reverberation, which sounds like someone pounding on metal piping with a hammer.
Vertical pipes at ends of runs are one method of preventing water hammer. T/F
True
Why can plastic pipe not typically be used between units in shared dwellings?
b/c it is combustible
Polybutylene piping failures seem to be concentrated most at
a. crimp rings
b. elbows in pipes
c. horizontal splits in piping
d. at the connection to fixtures
e. in vertical pipe runs only
crimp rings
Polybutylene supply piping should not be closer than 18 inches to a water heater. T/F
True
Can polybutylene piping be used on a hot water recirculating loop? Y/N
No
A house with several different styles of crimp rings should be a cause for concern. T/F
True
What is the approximate temperature rise in residential water heaters?
70 degrees
A water heater is termed a single-pass appliance because:
The water heater does not use a recirculating system, it sees the water only once
What is the biggest impact of the single-pass feature on a water heater?
It is constantly exposed to fresh water & so is more prone to corrosion than a boiler
Where is the burner located on gas- and oil-fired water heaters?
The burner is at the bottom of the tank
What is the component that introduces cold water near the bottom of a gas-fired water heater tank?
a. drip tube
b. relief valve
c. dip tube
d. baffle
e. vent
dip tube
What are the 2 methods of rating a water heater?
- The volume of water it can hold
- size of the burner
How do the methods of rating water heaters relate?
A large burner means a high recovery rate, which allows a smaller tank to be installed
Which type of water heater has the slowest recovery rate?
electric water heater
Which type of water heater has the fastest recovery rate?
oil-fired water heater
Water running out of the burner compartment on start-up of a gas water heater suggests:
condensation in the combustion chamber is running down through the center of the water heater & draining out the bottom.
Gas & oil-fired water heaters are not allowed in sleeping areas. T/F
True
How high above the floor should a gas or oil-fired water heater be in a garage?
a. 0 inches
b. 6 inches
c. 12 inches
d. 18 inches
e. 24 inches
18 inches
Where does the probe for the temperature/pressure relief valve sit in the tank?
top 6 in of tank
Where does the discharge tube from the temperature/pressure relief valve have to dump water in a cold climate?
6 to 12 inches above the floor beside the hot water tank
Where does the temp/pressure relief valve have to discharge water in a warm climate?
6 to 24 inches above grade level outside of the house
If we only need a pressure relief valve because the water heater has some internal temp control, where can this pressure relief valve be?
anywhere on the tank, or on piping near the tank in some jurisdictions
What is the purpose of a baffle or turbulator in a gas fired water heater?
to slow down the exhaust products as they move up through the water heater
Why is an explosion with propane more likely than with natural gas?
because propane is heavier than air, and can accumulate, especially in a low area
When would a fan-assisted gas water heater typically be used?
if the house has no chimney or a chimney too large for a water heater
What is the exhaust pipe material for a fan assisted water heater typically?
ABS or PVC piping
List the common problems found with fan-assisted gas water heaters:
- Inoperative
- blower intake obstructed
- poor venting arrangement
- poor blower wiring
Are fan-assisted water heaters condensing?
No
Function of a trap
Trap prevents sewer gases from entering the house through the fixture drain outlet