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
Briefly explain why a toilet does not need a trap.
toilet bowl itself is a trap
A toilet does not need a vent. T/F
False
A waste pipe is intended to carry solids only. T/F
False
Why in a cold climate is the trap portion of the drainage system most vulnerable to freezing?
only portion of the drainage system which always contains water
Briefly describe the purpose of a trap primer.
To ensure there is always water in a floor drain trap to prevent sewer odors entering the home
Briefly explain what is meant by a wet vent.
A wet vent occurs when the drain for one fixture is serving as the vent for another
List 7 different materials used for piping in drain, waste, and vent systems.
- copper
- ABS plastic
- PVC plastic
- east iron
- lead
- galvanized steel
- brass
- clay
Why are leaks more difficult to find in drain, water, and vent systems than is supply systems?
Pipes are usually idle; and water is not under pressure
Copper pipe doe snot rust. T/F
False
List 2 methods of reducing the freezing risk of pipes in a cold environment.
- insulating the pipe
- wrapping pipe w/heating cable
List 6 locations for possible cross connections in a residence.
- drain connector from dishwasher
- water softeners
- outside house bibbs w/hose attached
- lawn sprinkler system
- toilets
- trap primers
What is the implication of a cross connection?
Contamination of a potable water supply
What is the required slope for nearly horizontal pipes in a drain, waste, and vent systems?
1/4” to 1/2” fall per foot run
Pipe size should always increase as you move downstream & more fixtures join in. T/F
True
Why is PVC or ABS plastic piping usually allowed only in single-family homes?
it is combustible
What is the implication of poor manifolding?
clogging of pipes
Purpose of a trap.
prevent odors from entering the home through the plumbing fixtures
Every trap should be provided with some method of removal or cleaning. T/F
True
A running trap is a good idea because it provides extra protection. T/F
False
List 4 types of traps that are not permitted in residential construction.
- S-trap
- Drum trap
- Bell trap
- Crown vented trap
What is the typical maximum distance between the fixture and the trap?
24 inches
Minimum trap arm length
at least 2 pipes diameters
Implication of a trap arm that is too long?
siphoning the trap
It’s impossible for a trap to be too big. T/F
False
Where should the floor drain be located?
at the low point in the floor
Explain the purpose of a backwater valve.
protect the home against sewer back up
What is the purpose of the venting system?
equalize air pressure in the waste plumbing system so that the traps won’t siphon
List 5 common materials used in venting systems.
- copper
- galvanized steel
- cast iron
- ABS plastic
- PVC plastic
Briefly explain the simple test required to check the venting system when you test functional drainage from a fixture.
listen for gurgling as the last bit of water leaves the drain, smell for sewer odors
List 7 problems found with vents.
- missing
- ineffective/incomplete
- poor vent pipe arrangements
- too small or too long
- island venting problems
- vent termination problems
- automatic air vents
The vent is typically located upstream of the trap. T/F
False
Nearly horizontal vent pipes should slope slightly down away from the trap they are protecting. T/F
False
The vent diameter must be as large as the trap diameter. T/F
False
Briefly explain problems with venting kitchen island sinks
kitchen islands are not adjacent to walls; therefore the vent pipe is some distance from the island, often exceeding the maximum allowable distance between trap and vent
What is the minimum height of vent pipe above the roofline?
6 inches
At least how far should an outdoor vent termination be above an operable door?
a. 1 ft
b. 2 ft
c. 3 ft
d. 4 ft
e. 5 ft
2 ft
What are the 3 components required on the discharge line from a sewage ejector pump?
- union
- check valve
- gate valve
What is the typical vent size on a sewage ejector pump?
a. 1 1/4 in
b. 1 1/2 in
c. 2 in
d. 2 1/2 in
e. 3 in
2 inches
What is the purpose of the sewage ejector system?
To lift the waste from a toilet below the public or private sewer line, up into the sewer. These pumps are needed when waste can’t flow by gravity into the sewer system.
Why is a check valve necessary when a sewage ejector is connected to municipal sewers?
Protects the ejector tank & house fixtures that feed the tank from back-up of the municipal sewer system.
What are the functions of the 3 pipes connected to a sewage ejector pump?
Vent pipe vents sewer gases, the discharge pipe handles the waste, & drain pipe brings the waste into the pump.
Sewage ejector pumps should not vibrate significantly when running? T/F
True
What is the purpose of a high level alarm with a sewage ejector?
warn the occupants that the sewage ejector pump has failed
Surface cracking in an acrylic kitchen sink is not usually a concern b/c there is no leakage. T/F
True
Testing for loose wall hung basins is best done by putting all your weight on the basin. T/F
False
List 2 possible cross connections at basins & sinks
vegetable sprayer left lying in a sink; extendable faucets
Why is water hammer more common in a house with cartridge faucets than with compression faucets?
cartridge faucets can be opened & closed more quickly
List 8 common faucet problems.
- leaks/drips
- stiff/inoperative
- loose
- cross connection
- noisy
- damaged
- hot/cold reversed
- shower diverter inoperative
List 3 types of faucet-related noise.
- bang
- chatter
- whistle
How is a cross connection possible with a hose bibb?
With no backflow prevention device, outside water could be sucked into the plumbing system if the hose is attached, & the supply pressure drops below atmospheric pressure.
How is a cross connection with a hose bibb prevented?
install a backflow prevention device
List 7 common problems with hose bibbs
- leaks or drips
- stiff or inoperative
- no backflow prevention
- loose
- pipe frozen or split
- poor slope on a frost-free hose bibb
- mechanical damage
Describe in 2 sentences each, 2 types of hose bibbs.
- A stop & waste valve prevents water from sitting where the pipe will freeze by isolating the through-wall section of pipe, & draining the trapped water out through the waste valve.
- A frost-proof valve prevents water from sitting where the pipe will freeze by having the valve body remote from the hose bibb, & a slope to drain to the exterior.
Describe in 1 sentence a stop and waste valve.
valve shuts off water, drain cock drains water from pipe
What can cause a toilet to sweat?
Cold supply water on a warm, humid day can cause the toilet tank & toilet fill pipe to sweat, particularly if it is not allowed to warm up because of a running toilet.
How is a mixing valve used to stop a toilet sweating?
This valve mixes hot water with the cold water at the toilet supply. There is less incentive for condensation since the warmer water used to fill the toilet won’t cool the surrounding air to the dewpoint.
Running toilets are less prone to sweating b/c the water in the tank is constantly replenished. T/F
False
List 3 common leak locations in a two-piece toilet.
- bowl 2. tank 3. seal
Describe a test used to determine if the toilet connection to the drain piping is loose.
Grasp the bowl between your legs & try to move the bowl side to side & front to back. Do not use excessive force.
Does a toilet need to have a shutoff valve on the supply line? Y/N
Yes
What is the minimum width of space needed for a toilet installation?
a. 18 in
b. 24 in
c. 30 in
d. 36 in
e. no minimum
30 in
List 7 common bathtub problems.
- leaks
- rust
- surface defects
- cross connections
- not level
- overflow leaking
- slow drains
- loose or unstable
Why does it matter if the tub is slightly out of level?
The apron is usually sloped slightly so that water will drain back into the tub. If the tub is not level, water on the apron may drain away from the tub, damaging walls or floors.
Why are tile enclosures on exterior walls in cold climates more vulnerable than ones in warm climates?
vapor barrier & insulation details are often poorly done. Condensation damage is common in this area, as warm house air leaks into the wall & vapor condenses in the cold exterior wall cavity.
List 5 specific areas where tile enclosures are vulnerable to leakage.
- faucets
- soap dishes
- grab bars
- windows
- changes in direction or material
Briefly describe a test used to determine if the tiles in an enclosure are bonded well to the backer material.
tap or press on tiles; looking for spongy areas or give in the tiles or tiles that sound loose.
Because there is a watertight liner underneath the tiles in a shower stall base, the floor is not required to slope to drain. T/F
False
What is the minimum entrance width for shower stalls?
a. 18 in
b. 22 in
c. 26 in
d. 30 in
e. no minimum
22 in
Which way should a hinged shower door open in a shower stall?
outward
